Run mixed tests against 4.2 in main

Author: lhoguin

.github/workflows/test-mixed.yaml

@@ -1,4 +1,4 @@
-name: Test Mixed with 3.13
+name: Test Mixed with 4.2
 on:
   schedule:
     # at 2:20am on Sundays
@@ -8,7 +8,7 @@ on:
       previous_version:
         description: 'Previous version to test against'
         required: true
-        default: 'tags/v3.13.7'
+        default: 'tags/v4.2.0'
 jobs:
   test-mixed-clusters:
     name: Test mixed clusters
@@ -25,7 +25,7 @@ jobs:
     with:
       erlang_version: ${{ matrix.erlang_version }}
       elixir_version: ${{ matrix.elixir_version }}
-      previous_version: 'tags/v3.13.7'
+      previous_version: 'tags/v4.2.0'
       metadata_store: ${{ matrix.metadata_store }}
       mixed_clusters: true
-      ref: 'v4.2.x'
+      ref: 'main'