Improve dependabot merge message
As part of https://github.com/deephaven/infra/pull/308, we changed the default squashed merge message from commit message to PR description. I think for users, this is the better default.
Unfortunately, this makes the commit message for dependabot version bumps a hot mess by default.
Default commit message (from PR description): https://github.com/deephaven/deephaven-core/commit/9effbc8b7ac8b255ddb19de433a3bd88a018ee07
Original commit message (from PR commit): https://github.com/deephaven/deephaven-core/pull/5787/commits/9356ae6e7a4522a0c16bf696208461db63d24f41
I don't know if there are any GH options or Dependabot options we can set to make this better?
The best option right now is for the merger to manually edit the poor commit messages by copying the text from the commit.
Note: I've revived the PR branch https://github.com/deephaven/deephaven-core/tree/dependabot/gradle/testcontainers-1.20.0 to ensure the above original commit message does not get GCd.
Related https://github.com/dependabot/dependabot-core/issues/1986