ci: debug dependency discrepancy check

.github/workflows/elixir_deps_check.yaml

@@ -36,5 +36,14 @@ jobs:
         env:
           MIX_ENV: emqx-enterprise
           PROFILE: emqx-enterprise
+      - name: produced lock files
+        uses: actions/upload-artifact@v3
+        if: failure()
+        with:
+          name: produced_lock_files
+          path: |
+            mix.lock
+            rebar.lock
+          retention-days: 1
 
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