Test on HAProxy 3.4

Author: TimWolla

.github/workflows/test.yml

@@ -52,6 +52,7 @@ jobs:
         - "3.1"
         - "3.2"
         - "3.3"
+        - "3.4"
       fail-fast: false
     steps:
     - name: Install HAProxy ${{ matrix.haproxy-versions }}.