github: add CI run on oldest available Ubuntu

The builds keep failing for people with old headers.
Add the oldest OS available in the CI for max coverage.

Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

.github/workflows/c-cpp-old.yml

@@ -0,0 +1,17 @@
+name: C/C++ CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-22.04
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: make
+      run: make