infra: add dependabot for github actions

[AbeCoull]

Issue #, if available:

Description of changes:
This will keep our GH actions up to date.

Testing done:

Merge Checklist

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General

• I have read the CONTRIBUTING doc
• I used the commit message format described in CONTRIBUTING
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• I have added tests that prove my fix is effective or that my feature works (if appropriate)
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (65a7bb3) to head (9d0b9e0).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #179   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           99        99           
  Lines         1478      1478           
  Branches        27        27           
=========================================
  Hits          1478      1478           

Flag	Coverage Δ
	100.00% <ø> (ø)

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