Add project stuff for CI/make/etc

hack/ci/check_mods.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+set -e
+
+exit_code=0
+
+make mod
+git diff --exit-code go.mod go.sum || exit_code=$?
+
+if [ ${exit_code} -eq 0 ]; then
+	exit 0
+fi
+
+echo "please run \`make mod\` and check in the changes"
+exit ${exit_code}
+