Add a test to assert branch-alias is well defined (#1610)

Author: jderusse

.github/workflows/branch_alias.yml

@@ -31,7 +31,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "1.6-dev"
+            "dev-master": "1.5-dev"
         }
     }
 }