chore: only update rust code coverage job if rust code was updated

.github/workflows/codecov.yml

@@ -9,8 +9,26 @@ on:
     types: [opened, reopened, synchronize]
 
 jobs:
+  diff:
+    runs-on: ubuntu-latest
+    outputs:
+      isRust: ${{ steps.diff.outputs.isRust }}
+    steps:
+    - uses: actions/checkout@v2
+    - name: Detect Changes
+      uses: dorny/[email protected]
+      id: diff
+      with:
+        filters: |
+          isRust:
+            - '!(explorer|doc|.github)/**'
+            - '.github/workflows/bench.yml'
+
+
   codecov-grcov:
     name: Generate code coverage
+    needs: diff
+    if: github.event.pull_request.draft == false && needs.diff.outputs.isRust == 'true'
     runs-on: ubuntu-latest
     strategy:
       fail-fast: true