chore: no longer run renovate on v14 branch [skip ci] (#11975)

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11975
Reviewed-by: limiting-factor <limiting-factor@noreply.codeberg.org>
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>

Author: BeowulfR

.forgejo/renovate.json

@@ -9,7 +9,6 @@
   "baseBranchPatterns": [
     "$default",
     "/^v11\\.\\d+/forgejo$/",
-    "/^v14\\.\\d+/forgejo$/",
     "/^v15\\.\\d+/forgejo$/"
   ],
   "postUpdateOptions": ["gomodTidy", "gomodUpdateImportPaths", "npmDedupe"],