Use "v3.5.0-pre" to reference within-etcd modules

instead of v3.0.0-000101010000000-00000000000,
that might be misleading as we don't develop etcd v3.0.0 any longer.

This version is a virtual version and is not supposed to be tagged
within the repository. We should tag real versions like: 3.5.0-alpha.0.

Please notice that go.etcd.io/etcd/client/v2 will be versioned as `v2.305.0-pre`.
The reason is that client v2 must have v2 version. I propose a
convention to envode the major version as 100x in minor version to make
the association to the underlying repository clear, staying within v2
version family.

The change was generated using:
```
DRY_RUN=false TARGET_VERSION="v3.5.0-pre" ./scripts/release_mod.sh update_versions
```
diff --git a/go.mod b/go.mod
index 2fd43f53d..a41d019e7 100644
--- a/go.mod
+++ b/go.mod
@@ -19,13 +19,13 @@ require (
        github.com/mattn/go-runewidth v0.0.9 // indirect
        github.com/spf13/cobra v1.1.1
        go.etcd.io/bbolt v1.3.5
-       go.etcd.io/etcd/api/v3 v3.0.0-00010101000000-000000000000

client/v2/go.mod

@@ -5,8 +5,8 @@ go 1.15
 require (
 	github.com/json-iterator/go v1.1.10
 	github.com/modern-go/reflect2 v1.0.1
-	go.etcd.io/etcd/api/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/pkg/v3 v3.0.0-00010101000000-000000000000
+	go.etcd.io/etcd/api/v3 v3.5.0-pre
+	go.etcd.io/etcd/pkg/v3 v3.5.0-pre
 )
 
 replace (

client/v3/go.mod

@@ -7,8 +7,8 @@ require (
 	github.com/google/uuid v1.1.2
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/prometheus/client_golang v1.5.1
-	go.etcd.io/etcd/api/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/pkg/v3 v3.0.0-00010101000000-000000000000
+	go.etcd.io/etcd/api/v3 v3.5.0-pre
+	go.etcd.io/etcd/pkg/v3 v3.5.0-pre
 	go.uber.org/zap v1.16.0
 	google.golang.org/grpc v1.29.1
 	sigs.k8s.io/yaml v1.2.0

etcdctl/go.mod

@@ -11,12 +11,12 @@ require (
 	github.com/spf13/pflag v1.0.5
 	github.com/urfave/cli v1.22.4
 	go.etcd.io/bbolt v1.3.5
-	go.etcd.io/etcd/api/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v2 v2.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/pkg/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/raft/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/server/v3 v3.0.0-00010101000000-000000000000
+	go.etcd.io/etcd/api/v3 v3.5.0-pre
+	go.etcd.io/etcd/client/v2 v2.305.0-pre
+	go.etcd.io/etcd/client/v3 v3.5.0-pre
+	go.etcd.io/etcd/pkg/v3 v3.5.0-pre
+	go.etcd.io/etcd/raft/v3 v3.5.0-pre
+	go.etcd.io/etcd/server/v3 v3.5.0-pre
 	go.uber.org/zap v1.16.0
 	golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e
 	google.golang.org/grpc v1.29.1

go.mod

@@ -19,13 +19,13 @@ require (
 	github.com/mattn/go-runewidth v0.0.9 // indirect
 	github.com/spf13/cobra v1.1.1
 	go.etcd.io/bbolt v1.3.5
-	go.etcd.io/etcd/api/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v2 v2.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/pkg/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/raft/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/server/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/tests/v3 v3.0.0-00010101000000-000000000000
+	go.etcd.io/etcd/api/v3 v3.5.0-pre
+	go.etcd.io/etcd/client/v2 v2.305.0-pre
+	go.etcd.io/etcd/client/v3 v3.5.0-pre
+	go.etcd.io/etcd/pkg/v3 v3.5.0-pre
+	go.etcd.io/etcd/raft/v3 v3.5.0-pre
+	go.etcd.io/etcd/server/v3 v3.5.0-pre
+	go.etcd.io/etcd/tests/v3 v3.5.0-pre
 	go.uber.org/zap v1.16.0
 	golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e
 	google.golang.org/grpc v1.29.1

raft/go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/gogo/protobuf v1.3.1
 	github.com/golang/protobuf v1.3.5
 	github.com/pkg/errors v0.9.1 // indirect
-	go.etcd.io/etcd/pkg/v3 v3.0.0-00010101000000-000000000000
+	go.etcd.io/etcd/pkg/v3 v3.5.0-pre
 )
 
 // Bad imports are sometimes causing attempts to pull that code.

server/go.mod

@@ -27,11 +27,11 @@ require (
 	github.com/tmc/grpc-websocket-proxy v0.0.0-20200427203606-3cfed13b9966
 	github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2
 	go.etcd.io/bbolt v1.3.5
-	go.etcd.io/etcd/api/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v2 v2.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/pkg/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/raft/v3 v3.0.0-00010101000000-000000000000
+	go.etcd.io/etcd/api/v3 v3.5.0-pre
+	go.etcd.io/etcd/client/v2 v2.305.0-pre
+	go.etcd.io/etcd/client/v3 v3.5.0-pre
+	go.etcd.io/etcd/pkg/v3 v3.5.0-pre
+	go.etcd.io/etcd/raft/v3 v3.5.0-pre
 	go.uber.org/zap v1.16.0
 	golang.org/x/crypto v0.0.0-20201002170205-7f63de1d35b0
 	golang.org/x/lint v0.0.0-20200302205851-738671d3881b // indirect

tests/go.mod

@@ -25,13 +25,13 @@ require (
 	github.com/spf13/cobra v1.1.1
 	github.com/spf13/pflag v1.0.5
 	go.etcd.io/bbolt v1.3.5
-	go.etcd.io/etcd/api/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v2 v2.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/client/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/etcdctl/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/pkg/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/raft/v3 v3.0.0-00010101000000-000000000000
-	go.etcd.io/etcd/server/v3 v3.0.0-00010101000000-000000000000
+	go.etcd.io/etcd/api/v3 v3.5.0-pre
+	go.etcd.io/etcd/client/v2 v2.305.0-pre
+	go.etcd.io/etcd/client/v3 v3.5.0-pre
+	go.etcd.io/etcd/etcdctl/v3 v3.5.0-pre
+	go.etcd.io/etcd/pkg/v3 v3.5.0-pre
+	go.etcd.io/etcd/raft/v3 v3.5.0-pre
+	go.etcd.io/etcd/server/v3 v3.5.0-pre
 	go.uber.org/zap v1.16.0
 	golang.org/x/crypto v0.0.0-20201002170205-7f63de1d35b0
 	golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e