build: disable xapian under 3.12 python.

as documented in issue2551277

1.4.22 doesn't build with:

xapian_wrap.cc: In function ‘PyObject* PyInit__xapian()’:
xapian_wrap.cc:65031:116: error: ‘FLAG_NO_POSITIONS’ is not a member
    of ‘Xapian::QueryParser’
65031 |   SWIG_Python_SetConstant(d,"QueryParser_FLAG_NO_POSITIONS",
  SWIG_From_int(static_cast< int >(Xapian::QueryParser::FLAG_NO_POSITIONS)));

Author: rouilj

.github/workflows/ci-test.yml

@@ -205,7 +205,7 @@ jobs:
           # Change distutils.sysconfig... to just sysconfig and SO
           # to EXT_SUFFIX to get valid value.
           if [[ $PYTHON_VERSION == "3."* ]]; then sed -i -e '/PYTHON3_SO=/s/distutils\.//g' -e '/PYTHON3_SO=/s/"SO"/"EXT_SUFFIX"/g' configure; ./configure --prefix=$VIRTUAL_ENV --with-python3 --disable-documentation; fi
-          case "$PYTHON_VERSION" in nightly) echo skipping xapian build;; *) make && sudo make install; esac
+          case "$PYTHON_VERSION" in nightly|3.12*) echo skipping xapian build;; *) make && sudo make install; esac
 
       - name: Install pytest and other packages needed for running tests
         run: pip install flake8 mock pytest pytest-cov requests