Change doc theme to 'book'

RTD theam is not compatible with Sphinx 7.0+
https://github.com/readthedocs/readthedocs.org/issues/10279

Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>

doc/conf.py

@@ -68,7 +68,7 @@ exclude_patterns = [
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = 'default'
+html_theme = 'sphinx_book_theme'
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,

doc/requirements.txt

@@ -1,6 +1,7 @@
 wheel
 
 sphinx > 3.0
+sphinx-book-theme
 
 # convert markdown to rest
 # m2r2 fork is active in development and works with