[DEPENDABOT] integrate CompatHelper into Dependabot

[aelligp]

Whats the purpose of this PR?

• Bug fix
• New feature
• Documentation update
• Other, please explain

Describe it in more detail below:
Native GitHub Dependabot now handles Julia dependencies which means there's no need to have a special CompatHelper GH action. Plus this groups all PRs into one to avoid failing tests like in #429 which would require #419

Checklist

• The PR title is descriptive and starts with the appropriate tag: [BUGFIX], [ADDITION], [DOC], etc.
• New tests (either assessing the correct behaviour of new internal functions or the correctness of a miniapps or benchmarks) were added, or old tests were updated
• Affected miniapps have also been updated
• The new feature was added in a way that does not break public API
• New documentation related to the new feature was added
• The new code follows the contributor guidelines, in particular the Runic Style

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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