PGO update script: Connect to GitHub over HTTPS rather than SSH.

The `gh auth setup-git` command appears to configure Git as a credential
helper for `https`, not for SSH-based access. SSH access fails with the
host authenticity check.

Try to connect over HTTPS instead, to see if that works properly.
Otherwise we will have to provision `~/.ssh/known_hosts` and give the
agent a private SSH key for authentication.

PiperOrigin-RevId: 772156228

Author: EtiennePerot

.buildkite/scripts/pgo/commit-update.sh

@@ -36,7 +36,7 @@ export GIT_AUTHOR_EMAIL=gvisor-bot@google.com
 export GIT_COMMITTER_NAME=gvisor-bot
 export GIT_COMMITTER_EMAIL=gvisor-bot@google.com
 git commit -m "Update runsc profiles for PGO (profile-guided optimizations), $today."
-git push --set-upstream git@github.com:google/gvisor.git "$pgo_branch_name"
+git push --set-upstream https://github.com/google/gvisor.git "$pgo_branch_name"
 gh pr create \
   --title="Update runsc profiles for PGO (profile-guided optimizations), $today." \
   --body='This PR updates the runsc profiles for PGO (profile-guided optimizations).' \