CompatHelper: bump compat for DataGraphs to 0.3, (keep existing compat)

[ITensorBot]

This pull request changes the compat entry for the DataGraphs package from 0.2.7 to 0.2.7, 0.3.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.40%. Comparing base (989984a) to head (9db64fb).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #100      +/-   ##
==========================================
- Coverage   64.53%   64.40%   -0.14%     
==========================================
  Files          21       21              
  Lines         736      736              
==========================================
- Hits          475      474       -1     
- Misses        261      262       +1     

Flag	Coverage Δ
docs	0.00% <ø> (ø)

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