GitHub workflows are out of date

The GitHub workflows in this repo do not align with the module template. Specifically, `actions/cache` is still being used in an unsafe manner (we should be using the `checkout-and-setup` action).

This should fix:

- https://github.com/MetaMask/create-release-branch/security/code-scanning/6
- https://github.com/MetaMask/create-release-branch/security/code-scanning/5
- https://github.com/MetaMask/create-release-branch/security/code-scanning/4

## Acceptance Criteria

- `.github/workflows` in this repo matches the same directory in the module template.
- The Dependabot config should match the module template.
- The pull request template should match the module template (minus the final section).

Compare `.github/workflows`, the Dependabot config, and the pull request template with the module template, starting with the unsafe `actions/cache` usage and the `checkout-and-setup` action. Done means those areas match the module template, except for the final section of the pull request template, and the listed code-scanning findings are addressed.

Written by the indexing model from the issue text.