Test wip-ubuntu_latest.

Author: sobomax

.github/workflows/main.yml

@@ -78,6 +78,7 @@ jobs:
       mm-type: 'b2bua'
       mm-branch: ${{ matrix.mm-branch }}
       rtppc-type: ${{ matrix.rtppc-type }}
+      rtpp-image-tag: 'wip-ubuntu_latest'
       python-version: ${{ matrix.python-version }}
       artifact-files: 'b2bua.log'
     strategy: