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

[mtfishman]

This pull request changes the compat entry for the DataGraphs package from 0.2.13 to 0.2.13, 0.3 for package test.
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 71.43%. Comparing base (9b9ded5) to head (f1bc88d).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #324      +/-   ##
==========================================
- Coverage   71.45%   71.43%   -0.03%     
==========================================
  Files          81       81              
  Lines        4029     4029              
==========================================
- Hits         2879     2878       -1     
- Misses       1150     1151       +1     

Flag	Coverage Δ
docs	36.54% <ø> (-0.03%)	⬇️

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[mtfishman]

Superseded by #338 — same compat bump, opened by ITensorBot under the new automation account. Closing as duplicate.