* .github/workflows/linux.yml: Build and test on ubuntu-20.04 and ubuntu-22.04.


git-svn-id: https://svn.apache.org/repos/asf/serf/trunk@1909247 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 796afce..5356f3e 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -11,8 +11,11 @@
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ "ubuntu-20.04", "ubuntu-22.04" ]
 
+    runs-on: ${{ matrix.os }}
     steps:
       - name: Install prerequisites
         run: |