enable dependabot for GitHub actions

[mateuszbaran]

This should update our Github actions. See here for some details: https://github.com/SciML/MuladdMacro.jl/pull/37 .

[codecov[bot]]

Codecov Report

Merging #149 (8a89673) into master (79fc389) will decrease coverage by 0.12%. The diff coverage is n/a.

:exclamation: Current head 8a89673 differs from pull request most recent head 5f22543. Consider uploading reports for the commit 5f22543 to get more accurate results

@@            Coverage Diff             @@
##           master     #149      +/-   ##
==========================================
- Coverage   99.96%   99.84%   -0.12%     
==========================================
  Files          19       19              
  Lines        2529     2529              
==========================================
- Hits         2528     2525       -3     
- Misses          1        4       +3     

see 1 file with indirect coverage changes

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more