Enhance the check make target to ensure the Go version adheres to `…

…x.y.0`. (#930)

hack/check.sh

@@ -34,4 +34,15 @@ if [[ "$unformatted_files" ]]; then
   exit 1
 fi
 
-echo "All checks successful"
+echo "Checking Go version"
+GOVERSION=$(go list -f {{.GoVersion}} -m)
+if [[ $GOVERSION =~ ^[0-9]+\.[0-9]+\.0$ ]]; then
+  # Go version is valid, adheres to x.y.0 version
+  exit 0
+else
+  echo "Go version is invalid, please adhere to x.y.0 version"
+  echo "See https://github.com/gardener/etcd-druid/pull/925"
+  exit 1
+fi
+
+echo "All checks successful"