Remove the beta block.

.github/workflows/checks.yml

@@ -36,12 +36,6 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
 
-    - name: Install system libraries
-      if: contains(matrix.python-version, 'beta')
-      run: |
-        sudo apt-get update
-        sudo apt-get install libxml2-dev libxslt-dev
-
     - name: Run check
       env: ${{ matrix.env }}
       run: |