Auto-bump PRs failing to merge inconsistently/fluky

[dbeatty10]

This is happening very rarely and for unknown reasons.

Recent examples:

• HubCap: Bump package versions #2179
• HubCap: Bump package versions #2191

Since the PR opened the following hour has been consistently succeeding the impact is limited to:

• hour delay for new package version to be released to hub.getdbt.com
• stale PR with merge conflicts that needs to be closed manually

It's not currently a high priority to fix this.

It is reminiscent of:

• Only one auto-merge per hour can cause latency for new package versions #1765
• Duplicated HubCap bump PRs with merge conflicts #1484