build(deps): add libstdcxx pin, bump CondaPkg

[cjdoris]

Add libstdcxx to CondaPkg.toml with version "<=julia" to improve libstdc++ compatibility with the Julia toolchain. Bump CondaPkg compat to 0.2.30 to leverage related fixes. Update release notes to reflect the improved compatibility.

[thchr]

For anyone potentially hitting the issue I hit just now and tracing it to here: I believe pulling in this update in my main environment (i.e. up-to-date PythonCall/CondaPkg), but not another project-specific environment (i.e. v0.9.26 PythonCall/v0.2.29 CondaPkg), produced the following error:

julia>using [some local package involving a CondaPkg.toml file] CondaPkg Found dependencies:/home/tchr/.julia/packages/PythonCall/avYrV/CondaPkg.toml CondaPkg Found dependencies:/mnt/c/Users/tchr/[some local folder]/julia/SymmetryBases/CondaPkg.toml CondaPkg Found dependencies:/home/tchr/.julia/environments/v1.11/CondaPkg.toml CondaPkg Found dependencies:/mnt/c/Users/tchr/[some local folder]/julia/MPBUtils/CondaPkg.toml CondaPkg Found dependencies:/home/tchr/.julia/packages/PythonCall/IOKTD/CondaPkg.toml CondaPkg Resolving changes + libstdcxx + libstdcxx-ng + nodefinder (pip) + numpy + openssl + phasemap (pip) + pymeep + pynormaliz (pip) + python + scipy + uv CondaPkg Initialising pixi │ /home/tchr/.julia/artifacts/cefba4912c2b400756d043a2563ef77a0088866b/bin/pixi │ init │ --format pixi └ /mnt/c/Users/tchr/[some local folder]/julia/BandGraphs/test/.CondaPkg ✔ Created /mnt/c/Users/tchr/[some local folder]/julia/BandGraphs/test/.CondaPkg/pixi.toml CondaPkg Wrote /mnt/c/Users/tchr/[some local folder]/julia/BandGraphs/test/.CondaPkg/pixi.toml │ [dependencies] │ openssl =">=3, <3.6, >=3, <3.6" │ libstdcxx ="<=julia" │ uv =">=0.4" │ libstdcxx-ng =">=3.4,<14.0, >=3.4,<14.0" │ pymeep ="*" │ numpy ="*" │ scipy ="*" │ │ [dependencies.python] │ channel ="conda-forge" │ build ="*cpython*" │ version =">=3.9,<4, >=3.8,<4" │ │ [project] │ name =".CondaPkg" │ platforms = ["linux-64"] │ channels = ["conda-forge"] │ channel-priority ="strict" │ description ="automatically generated by CondaPkg.jl" │ │ [pypi-dependencies] │ phasemap ="*" │ nodefinder ="*" └ pynormaliz ="*" CondaPkg Installing packages │ /home/tchr/.julia/artifacts/cefba4912c2b400756d043a2563ef77a0088866b/bin/pixi │ install └ --manifest-path /mnt/c/Users/tchr/[some local folder]/julia/BandGraphs/test/.CondaPkg/pixi.toml Error:× failed to solve the conda requirements of 'default''linux-64' ╰─▶ Cannot solve the request because of: No candidates were found for libstdcxx <=julia. ERROR: InitError: failed process: Process(setenv(`/home/tchr/.julia/artifacts/cefba4912c2b400756d043a2563ef77a0088866b/bin/pixi install --manifest-path '/mnt/c/Users/tchr/[some local folder]/julia/BandGraphs/test/.CondaPkg/pixi.toml'`, [...............]

The error was resolved by updating my out-of-date project environment to the latest PythonCall.jl version - but a bit tricky that one environment's PythonCall/CondaPkg versions could somehow influence another's.