Fix CentOS Stream 9 CI: remove ninja-build (not in default repos)

ninja-build is not available in the CentOS Stream 9 BaseOS/AppStream
repositories. It is only available via CRB or EPEL. Since cmake falls
back to Unix Makefiles when ninja is not found, removing it is the
simplest fix.

Co-authored-by: Andrey G <networmix@gmail.com>

Author: cursoragent

.github/workflows/tests.yml

@@ -39,7 +39,7 @@ jobs:
       - name: Install system dependencies
         run: |
           dnf install -y \
-            gcc gcc-c++ make cmake ninja-build git \
+            gcc gcc-c++ make cmake git \
             python${{ matrix.python-version }} \
             python${{ matrix.python-version }}-devel \
             python${{ matrix.python-version }}-pip \