[ECO-2796] Update processor submodule GitHub Actions check to work wi…

…th `emojicoin-arena` and `arena` branches (#570)

.github/workflows/submodule.yaml

@@ -5,10 +5,17 @@ jobs:
     steps:
     - uses: 'actions/checkout@v3'
     - run: 'git submodule update --init --recursive src/rust/processor'
-    - run: 'git fetch'
-      working-directory: 'src/rust/processor'
-    - run: 'git diff --quiet origin/emojicoin-dot-fun'
+    # yamllint disable rule:indentation
+    - run: |
+        branch="${{ github.head_ref || github.ref_name }}"
+        target_branch="emojicoin-dot-fun"
+        if [ "$branch" = "arena" ]; then
+          target_branch="emojicoin-arena"
+        fi
+        git fetch origin $target_branch
+        git diff --quiet origin/$target_branch
       working-directory: 'src/rust/processor'
+      # yamllint enable rule:indentation
 name: 'Ensure correct version of processor submodule'
 'on':
   pull_request: null