ci: add dependabot

[SKY-ALIN]

Dependabot will make PRs to update dependencies weekly, it helps keep dependencies up to date. You don't need to add something to the repository's settings or this PR, it'll start to work after the merge.

GitHub page about it

An article about it on Medium

[coveralls]

Pull Request Test Coverage Report for Build 5405379977

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 63.477%

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Totals
Change from base Build 5187478476:	0.0%
Covered Lines:	471
Relevant Lines:	742

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💛 - Coveralls

[dlaehnemann]

As with the rust-bio PR, I'd move this new .yml file into the .github/workflows directory, so that all workflows are in one place. Other than that, this is good to go.

Thanks a lot for the contribution!

[SKY-ALIN]

I suppose it's not possible because it must be stored exactly in the .github folder:

You must store this file in the .github directory of your repository. When you add or update the dependabot.yml file, this triggers an immediate check for version updates.

Source: https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#about-the-dependabotyml-file

[dlaehnemann]

Nice, so it also works in sub-directories.