hack/tools: drop dependency on golangci-lint

Depending on the more recent golangci-lint 1.43.0 also pulled in a newer mock
package, which caused problems when trying to use the logcheck plugin in
Kubernetes because there were problems with generated mock files when using the
newer mock.

golangci-lint isn't actually needed (anymore?) for building the plugin, so a
"go mod tidy" removed it.

hack/tools/go.mod

@@ -3,7 +3,6 @@ module k8s.io/klog/hack/tools
 go 1.15
 
 require (
-	github.com/golangci/golangci-lint v1.43.0
 	golang.org/x/exp v0.0.0-20210220032938-85be41e4509f
-	golang.org/x/tools v0.1.7
+	golang.org/x/tools v0.1.0
 )