v3: ensure that dep can import v3.0.0

These symlinks ensure that "dep" can still import v3.0.0. Without
them, importing fails when it encounters the
github.com/kubernetes-csi/csi-test/v3 because there's no code under
that path without the symlinks. Symlinks work for files, but not for
directories (probably due to a check in dep which expects directories
for packages).

Upstream suggests to move the code itself ("Major subdirectory",
https://github.com/golang/go/wiki/Modules#releasing-modules-v2-or-higher). But
that messes with git history. Symlinks are simpler, but have the
disadvantage of only working on Unix. Users on Windows will have to
use "go mod" for importing.

v3/driver/driver-controller.go

@@ -0,0 +1 @@
+../../driver/driver-controller.go

v3/driver/driver-node.go

@@ -0,0 +1 @@
+../../driver/driver-node.go

v3/driver/driver.go

@@ -0,0 +1 @@
+../../driver/driver.go

v3/driver/driver.mock.go

@@ -0,0 +1 @@
+../../driver/driver.mock.go

v3/driver/mock.go

@@ -0,0 +1 @@
+../../driver/mock.go

v3/mock/cache/SnapshotCache.go

@@ -0,0 +1 @@
+../../../mock/cache/SnapshotCache.go

v3/mock/service/controller.go

@@ -0,0 +1 @@
+../../../mock/service/controller.go

v3/mock/service/identity.go

@@ -0,0 +1 @@
+../../../mock/service/identity.go

v3/mock/service/node.go

@@ -0,0 +1 @@
+../../../mock/service/node.go

v3/mock/service/service.go

@@ -0,0 +1 @@
+../../../mock/service/service.go

v3/pkg/sanity/cleanup.go

@@ -0,0 +1 @@
+../../../pkg/sanity/cleanup.go

v3/pkg/sanity/controller.go

@@ -0,0 +1 @@
+../../../pkg/sanity/controller.go

v3/pkg/sanity/identity.go

@@ -0,0 +1 @@
+../../../pkg/sanity/identity.go

v3/pkg/sanity/node.go

@@ -0,0 +1 @@
+../../../pkg/sanity/node.go

v3/pkg/sanity/sanity.go

@@ -0,0 +1 @@
+../../../pkg/sanity/sanity.go

v3/pkg/sanity/tests.go

@@ -0,0 +1 @@
+../../../pkg/sanity/tests.go

v3/pkg/sanity/util.go

@@ -0,0 +1 @@
+../../../pkg/sanity/util.go

v3/utils/grpcutil.go

@@ -0,0 +1 @@
+../../utils/grpcutil.go

v3/utils/safegoroutinetester.go

@@ -0,0 +1 @@
+../../utils/safegoroutinetester.go