git_auto_update: Added check if no update is required

roles/git_auto_update/templates/update.sh

@@ -25,10 +25,14 @@ git remote set-url origin "$REPO";
 
 git fetch --recurse-submodules --tags > /dev/null;
 TAG=$(git tag --list | grep "^$PREFIX" | sort -r | head -n 1);
+CURRENT=$(git rev-parse --abbrev-ref HEAD);
 
 if [ -z "$TAG" ]; then
   error "No release tag found";
   exit 1;
+elif [ "$TAG" = "$CURRENT" ]; then
+  # No update required
+  exit 0;
 elif [ -z "$GPG_FINGERPRINT" ] || (git verify-tag --raw "$TAG" 2>&1 | grep --fixed-strings " VALIDSIG $GPG_FINGERPRINT ") > /dev/null; then
   git reset --quiet --hard --recurse-submodules;
   git checkout --quiet --recurse-submodules "$TAG";