fix: use git ls-remote to detect stable branches

Signed-off-by: John Molakvoæ <skjnldsv@users.noreply.github.com>
Signed-off-by: skjnldsv <skjnldsv@protonmail.com>

Author: skjnldsv

.github/workflows/generate-top-index.yml

@@ -28,7 +28,7 @@ jobs:
     - name: Get stable branches
       id: branch
       run: |
-        branches=$(git branch -r | grep -E 'origin/stable[0-9]+' | sed 's/.*stable//' | sort -n -r | tr '\n' ' ')
+        branches=$(git ls-remote --heads origin "heads/stable[0-9][0-9]"| awk '{gsub(/^refs\/heads\/stable/, "", $2); print $2}' | sort -n -r | tr '\n' ' ')
         echo "branches=$branches" >> $GITHUB_OUTPUT
 
     - name: Setup php

.github/workflows/sphinxbuild.yml

@@ -119,7 +119,7 @@ jobs:
         current_branch="${GITHUB_REF#refs/heads/}"
 
         # Find the highest numbered stable branch
-        highest_stable=$(git branch -r | grep -E 'origin/stable[0-9]+' | sed 's/.*stable//' | sort -n | tail -1)
+        highest_stable=$(git ls-remote --heads origin 'heads/stable[0-9][0-9]' | sed 's?.*refs/heads/stable??' | sort -n | tail -1)
         highest_stable_branch="stable${highest_stable}"
 
         echo "Current branch: $current_branch"