Add a script to check if go.mod and go.sum are up-to-date

Signed-off-by: Guillaume Lours <guillaume.lours@docker.com>

scripts/validate/check-go-mod

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+#   Copyright The Compose Specification Authors.
+
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+
+#       http://www.apache.org/licenses/LICENSE-2.0
+
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+
+set -uo pipefail
+mkdir -p /tmp/gomod
+cp go.* /tmp/gomod/
+go mod tidy
+DIFF=$(diff go.mod /tmp/gomod/go.mod && diff go.sum /tmp/gomod/go.sum)
+if [ "$DIFF" ]; then
+    echo
+    echo "go.mod and go.sum are not up to date"
+    echo
+    echo "$DIFF"
+    echo
+    exit 1
+else
+    echo "go.mod is correct"
+fi;