Enable GHA for qpid-jms-1.x branch (#633)

Author: jiridanek

.github/workflows/maven.yml

@@ -5,9 +5,10 @@ name: Java CI with Maven
 
 on:
   push:
-    branches: [ main ]
+    branches: [ main, qpid-jms-1.x ]
   pull_request:
-    branches: [ main ]
+    branches: [ main, qpid-jms-1.x ]
+  workflow_dispatch:
 
 env:
   # https://maven.apache.org/configure.html#maven_args-environment-variable