Description of problem:

This PR gets auto created but it consistently fails at this step. In the most recent situation, I merged a PR in the 1.2.x branch. After this, theversion PR was created but it failed with the error:

x Unable to query SCM: git error: fatal: bad object

0000000000000000000000000000000000000000

`-> git error: fatal: bad object 0000000000000000000000000000000000000000

It's looking for the previous commit in the PR but since this is the initial commit, a series of zeros are returned.

A subsequent PR was merged in the 1.2.x branch which rebased the version PR. It failed again with the error:

x Unable to query SCM: git error: fatal: bad object

b1095be595a58e4e30504fd1142e529cfb85dc17

`-> git error: fatal: bad object b1095be595a58e4e30504fd1142e529cfb85dc17

The commit hash `b1095be595a58e4e30504fd1142e529cfb85dc17` refers to the commit hash in the previously failed job which no longer exists because the PR was rebased.

Since there can only be one version PR in a changeset-release branch, should we be getting the previous commit hash from the branch rather than the PR commit?

Prerequisites (if any, like setup, operators/versions):

Steps to Reproduce

1. <steps>

Actual results:

"Update and commit files" step fails

Expected results:

"Update and commit files" step should pass

Reproducibility (Always/Intermittent/Only Once):

Build Details:

Additional info (Such as Logs, Screenshots, etc):