squash! .github: actions: add testing for unrelesed ubuntu versions

.github: actions: add testing for unreleased ubuntu versions

Author: whitty

.github/workflows/main.yml

@@ -9,8 +9,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        - os: 25.04
-          image_version: feature-github_actions
+        os:
+          - 25.04
+        image_version: feature-github_actions
     container:
       image: ghcr.io/whitty/gh_ubuntu_${{ matrix.os }}:${{ matrix.image_version }}