MNT: bump to main branch of c-blosc to fix gcc15 compilation

[tacaswell]

close #750

[Description of PR]

TODO:

• Unit tests and/or doctests in docstrings
• Tests pass locally
• [/] Docstrings and API docs for any new/modified user-facing classes and functions
• [/] Changes documented in docs/release.rst
• [/] Docs build locally
• GitHub Actions CI passes
• [/] Test coverage to 100% (Codecov passes)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.92%. Comparing base (506c89b) to head (ffa69ad).

❌ Your project check has failed because the head coverage (90.92%) is below the target coverage (100.00%). You can increase the head coverage or adjust the target coverage.

❗ There is a different number of reports uploaded between BASE (506c89b) and HEAD (ffa69ad). Click for more details.

HEAD has 10 uploads less than BASE

Flag	BASE (506c89b)	HEAD (ffa69ad)
	15	5

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #772      +/-   ##
==========================================
- Coverage   99.96%   90.92%   -9.04%     
==========================================
  Files          64       64              
  Lines        2789     2789              
==========================================
- Hits         2788     2536     -252     
- Misses          1      253     +252     

see 2 files with indirect coverage changes

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[tacaswell]

Looks like the CI failures are fixed by #766 ?