CompatHelper: bump compat for SymPy to 2 for package test, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the SymPy package from 1 to 1, 2 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.

[jverzani]

@ranocha I see two types of errors. One coming from unsatisfiable requirements, the other like

https://github.com/ranocha/BSeries.jl/actions/runs/7016687290/job/19088404156?pr=182#step:7:215

That one is unexpected, as SymPy seems to be not simplifying as it had previously. I tried tracking things down, but didn't see where the issue is to be found. Am I reading this correctly?

[ranocha]

Yes, that's also what I get from it. It seems that it doesn't simplify (1/h) * h == 1 anymore.

[jverzani]

Yes, it is quite odd. I can't seem to not get the simplification trying combinations of 1/h, inv(h), h^(-1) and various assumptions when I work directly with SymPy. I kept the same recipe for Latexify and it seems to be called when I run within BSeries. If I'm following things correctly -- and that is a shaky assumption -- only the 1/h is being run through latexify in the recipe, and this becomes a string, so no cancellation can occur.

[ranocha]

I needed to update the package extension in #212 to fix the issue: I needed to specialize on Type{SymPy.Sym{SymPy.PyCall.PyObject}} instead of Type{SymPy.Sym} to make it work.