CI: run with standard mod_http2

We used to include a special mod_h2 in our CI that supports the
directive H2MaxDataFrameLen for test_02_20. Since then, ubuntu-lastest
includes a more recent apache httpd. Let's see if we can live without
the special.

Closes #15353

.github/workflows/linux.yml

@@ -46,8 +46,6 @@ env:
   # renovate: datasource=github-tags depName=Mbed-TLS/mbedtls versioning=semver registryUrl=https://github.com
   mbedtls-version: 3.6.2
   # renovate: datasource=github-tags depName=icing/mod_h2 versioning=semver registryUrl=https://github.com
-  mod_h2-version: 2.0.29
-  # renovate: datasource=github-tags depName=nibanks/msh3 versioning=semver registryUrl=https://github.com
   msh3-version: 0.6.0
   # renovate: datasource=github-tags depName=awslabs/aws-lc versioning=semver registryUrl=https://github.com
   awslc-version: 1.37.0
@@ -605,32 +603,6 @@ jobs:
         run: |
           sudo python3 -m pip install --break-system-packages -r tests/http/requirements.txt
 
-      - name: cache mod_h2
-        if: contains(matrix.build.install_steps, 'pytest')
-        uses: actions/cache@3624ceb22c1c5a301c8db4169662070a689d9ea8 # v4
-        id: cache-mod_h2
-        env:
-          cache-name: cache-mod_h2
-        with:
-          path: /home/runner/mod_h2
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ env.mod_h2-version }}
-
-      - name: 'build mod_h2'
-        if: contains(matrix.build.install_steps, 'pytest') && steps.cache-mod_h2.outputs.cache-hit != 'true'
-        run: |
-          cd $HOME
-          git clone --quiet --depth=1 -b v${{ env.mod_h2-version }} https://github.com/icing/mod_h2
-          cd mod_h2
-          autoreconf -fi
-          ./configure
-          make
-
-      - name: 'install mod_h2'
-        if: contains(matrix.build.install_steps, 'pytest')
-        run: |
-          cd $HOME/mod_h2
-          sudo make install
-
       - name: 'run pytest'
         if: contains(matrix.build.install_steps, 'pytest')
         env: