V2315 changes

[spxiwh]

Need to make what is hopefully one final release on the v23 release branch to include the new pegasus 5.1.2 release.

I think this should now be ready to merge. It basically contains:

• Some changes to the various github tests to make them work
  • The test workflows now run with 5.1.X (matching the main branch, which actually still runs with 5.1.1)
  • The tutorial tests are disabled ... The tutorials require main PyCBC and shouldn't be tested on release branches like this one
• Merging the "support for pegasus 5.1.X" patch Support for pegasus v5.1.1 #5142 ... No further changes are needed for 5.1.1
• Force pegasus 5.1.2 dependencies
• Restrict a bunch of other dependencies to "less than whatever it was at the end of 2024"
• Added a SINGULARITY requirement for OSG as recommended by James