ci: fix 403 on Edgheog docs push

staple-actions configures a global git insteadOf rewrite during mix deps.get,
converting GitHub SSH/HTTPS remotes to HTTPS with github.token credentials. That
makes the final docs push use the actions token instead of the deploy key and
fail with 403.

Remove the rewrite before push and reset origin to the SSH remote so the deploy
key is used.

Signed-off-by: Luca Zaninotto <luca.zaninotto@secomind.com>

Author: lusergit

.github/workflows/docs-ci.yaml

@@ -103,6 +103,6 @@ jobs:
           echo "${{ secrets.publish-key }}" | ssh-add -
           mkdir -p ~/.ssh/
           ssh-keyscan github.com >> ~/.ssh/known_hosts
-          git remote add topush "git@github.com:edgehog-device-manager/docs.git"
-          git fetch topush
-          git push topush main
+          git config --global --unset-all url."https://${{ github.token }}:x-oauth-basic@github.com/".insteadOf || true
+          git remote set-url origin git@github.com:edgehog-device-manager/docs.git
+          git push origin main