test: add test for HTTP/2 corruption as reported in #10525

- adding test_02_20 for reproducing the situation
- using recently released mod_h2 Apache module
- skipping test if an older version is installed
- adding installation of current mod_h2 to github pytest workflow

This reproduces the error reliable (for me) on the lib/http2.c version
of curl 7.88.0. And passes with the recent curl master.

Closes #10534

.github/workflows/pytest.yml

@@ -80,6 +80,15 @@ jobs:
         make install
       name: 'install nghttp2'
 
+    - run: |
+        git clone --depth=1 -b master https://github.com/icing/mod_h2
+        cd mod_h2
+        autoreconf -fi
+        ./configure PKG_CONFIG_PATH="$HOME/all/lib/pkgconfig"
+        make
+        sudo make install
+      name: 'install mod_h2'
+
     - uses: actions/checkout@v3
 
     - run: autoreconf -fi