PyPi publish issue (documentation formatting)

[rekt-hard]

When trying to publish on pypi, an error is thrown. It looks like the structure of CHANGES.rst and README.rst should be harmonized, by using the same level for sections and/or title(s).

Pipeline with error log can be found here: https://github.com/tu-graz-library/invenio-curations/actions/runs/11383954973/job/31670654326#step:7:22

Just in case it is not available anymore, here is the relevant part:

Checking dist/invenio_curations-0.1.0-py2.py3-none-any.whl: FAILED
ERROR    `long_description` has syntax errors in markup and would not be        
         rendered on PyPI.                                                      
         line 276: Severe: Title level inconsistent:                            
                                                                                
         Changes                                                                
         =======                                                                
WARNING  `long_description_content_type` missing. defaulting to `text/x-rst`.   
Checking dist/invenio-curations-0.1.0.tar.gz: FAILED
ERROR    `long_description` has syntax errors in markup and would not be        
         rendered on PyPI.                                                      
         line 276: Severe: Title level inconsistent:                            
                                                                                
         Changes                                                                
         =======                                                                
WARNING  `long_description_content_type` missing. defaulting to `text/x-rst`.