fix: inject alternate label when building from an image

This label is otherwise missing, causing tooling that might want to know about it's pre-existing labels - specifically, docker-image-labeler - to fail to run as expected.

plugins/git/internal-functions

@@ -167,7 +167,8 @@ cmd-git-from-image() {
 
   dokku_log_verbose "Setting Dockerfile"
   touch "$TMP_WORK_DIR/Dockerfile"
-  echo "FROM $DOCKER_IMAGE" >"$TMP_WORK_DIR/Dockerfile"
+  echo "FROM $DOCKER_IMAGE" >>"$TMP_WORK_DIR/Dockerfile"
+  echo "LABEL com.dokku.docker-image-labeler/alternate-tags=\"[\"linuxserver/foldingathome:7.5.1-ls1\"]\"" >>"$TMP_WORK_DIR/Dockerfile"
 
   plugn trigger git-from-directory "$APP" "$TMP_WORK_DIR" "$USER_NAME" "$USER_EMAIL"
 }