Upper case commit message after prefix

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Feature description

It would be cool if https://docs.github.com/en/code-security/dependabot/working-with-dependabot/dependabot-options-reference#commit-message-- has an option specify that the commit message after the prefix should start with an upper-case.

For example, I wish I could configure it to make https://github.com/enola-dev/enola/commit/a663f46a41abf9e696a9f174f30c8d4e619703fe to be _"build(deps): **B**ump "_ instead of _"build(deps): bump "_ for consistency in that project.

So the ⏮ opposite of #10586. 🏮

Start with the Dependabot commit-message configuration described in the linked options reference, then compare the requested behavior with the opposite change in issue #10586. Locate the existing handling and tests for commit-message prefixes; done means an option can produce an uppercase first character after the prefix without changing the default behavior.

Written by the indexing model from the issue text.