chore: add dependabot auto-merge

[moorec-aws]

What was the problem/requirement? (What/Why)

Add auto-merge to dependabot PRs if all status checks pass.

What was the solution? (How)

• Add a second approval to meet two approval requirements.
• Add an action to enable auto-merge with squash
• Update hatch.toml so that python-semantic-release is installed using the requirements-release.txt.

https://docs.github.com/en/code-security/dependabot/working-with-dependabot/automating-dependabot-with-github-actions

What is the impact of this change?

Dependabot PRs will now automerge if all mandatory status checks pass.

How was this change tested?

Tested in a developer github account

Was this change documented?

no

Is this a breaking change?

no