fix: insert version tag for docker only if it’s a semver

hooks/post_checkout

@@ -9,6 +9,13 @@ IFS=: read DOCKER_REPO CACHE_TAG <<< $IMAGE_NAME
 echo "repo=${DOCKER_REPO}"
 echo "tag=${CACHE_TAG}"
 
+SEMVER_REGEX="^(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)$"
+
+if ! [[ "$CACHE_TAG" =~ $SEMVER_REGEX ]]; then
+  echo Not a semver tag - skipping
+  exit
+fi
+
 # Write the tag to package.json>version so that "renovate --version" is correct
 
 sed -i.bak "s/0.0.0-semantic-release/${CACHE_TAG}/" package.json