CompatHelper: bump compat for OrdinaryDiffEqSymplecticRK in [weakdeps] to 2, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the OrdinaryDiffEqSymplecticRK package from 1.10 to 1.10, 2.
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 88.97%. Comparing base (a98e178) to head (e516904).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1158   +/-   ##
=======================================
  Coverage   88.97%   88.97%           
=======================================
  Files         129      129           
  Lines        9980     9980           
=======================================
  Hits         8880     8880           
  Misses       1100     1100           

Flag	Coverage Δ
total	88.97% <ø> (ø)
unit	67.65% <ø> (ø)

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