Limit scipy to version before 1.12 which introduces a breaking change and unfreeze sphinx version

[gabemery]

The breaking change I encountered is fixed in gammapy main branch but not in a release yet.

Error during lstchain tests with the latest scipy :

../../../micromamba-root/envs/lst-dev/lib/python3.10/site-packages/gammapy/utils/roots.py:9: in <module>
   BAD_RES = RootResults(root=np.nan, iterations=0, function_calls=0, flag=0)
E   TypeError: RootResults.__init__() missing 1 required positional argument: 'method'

'method' is introduced in scipy 1.12.0

EDIT Daniel Morcuende: I unfreeze the version of sphinx that was being used (~4) because it was giving problems in the docs building:

Sphinx version error:
The sphinxcontrib.applehelp extension used by this project needs at least Sphinx v5.0; it therefore cannot be built with this version.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (089891d) 74.22% compared to head (acce0df) 74.22%.

❗ Current head acce0df differs from pull request most recent head 5811da6. Consider uploading reports for the commit 5811da6 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1201   +/-   ##
=======================================
  Coverage   74.22%   74.22%           
=======================================
  Files         130      130           
  Lines       13279    13279           
=======================================
  Hits         9857     9857           
  Misses       3422     3422           

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[rlopezcoto]

Thanks @gabemery ! I opened #1202 to remember that we can follow later scipy releases whenever we do it for gammapy