Update Go test matrix to add Go v1.18

* Update `checkout` and `setup-go` Github Actions
* Remove `golint` since its deprecated
* Drop Go v1.16

.github/workflows/test.yaml

@@ -13,18 +13,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go: ['1.16', '1.17']
+        go: ['1.17', '1.18']
     steps:
       - name: setup
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v3
         with:
           go-version: ${{matrix.go}}
 
       - name: checkout
-        uses: actions/checkout@v2
-
-      - name: tools
-        run: go get golang.org/x/lint/golint
+        uses: actions/checkout@v3
 
       - name: test
         run: make

Makefile

@@ -1,5 +1,5 @@
 .PHONY: all
-all: test vet lint fmt
+all: test vet fmt
 
 .PHONY: test
 test:
@@ -9,10 +9,6 @@ test:
 vet:
 	@go vet -all .
 
-.PHONY: lint
-lint:
-	@golint -set_exit_status ./...
-
 .PHONY: fmt
 fmt:
 	@test -z $$(go fmt ./...)

sling_test.go

@@ -769,7 +769,7 @@ func TestReceive_success_nonDefaultDecoder(t *testing.T) {
 			<temperature>10.5</temperature>
 		</response>`
 		fmt.Fprintf(w, xml.Header)
-		fmt.Fprintf(w, data)
+		fmt.Fprint(w, data)
 	})
 
 	endpoint := New().Client(client).Base("http://example.com/").Path("foo/").Post("submit")