Improve accuracy and detail of release notes

[austin-hall-skylight]

What needs to be done

• Update repo settings to use pull request title and description as squashed and merged commit message
• Update release workflow to use commit messages since last release instead of closed pull request titles

Why it needs to be done

Release notes currently include PR's that have been closed but not merged. This will fix that error as well as giving us more detailed information about each PR that is included in the release.

Acceptance Criteria

• Release notes contain the title and description for each merged pull request included in the release
• Pull requests that have been closed but not merged are not included in the release notes

Technical Notes

• PR commit message settings can be found in Settings > General > Pull Requests > Default commit message (new value should be Pull request title and description)
• Workflow changes will take place in .github/workflows/createNewRelease.yaml, step "Generate release notes"

Additional context

n/a