ci: provide OS to matrix build

Author: nschonni

.github/workflows/build-test.yml

@@ -51,7 +51,7 @@ jobs:
     if: ${{ fromJson(needs.gen-matrix.outputs.matrix) }}
     needs: gen-matrix
     name: build
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     strategy:
       fail-fast: false

genMatrix.js

@@ -63,6 +63,7 @@ const getDockerfileMatrixEntry = (file) => {
   return {
     version,
     variant,
+    os: 'ubuntu-22.04'
   };
 };