Improve path-filtering rules on unit test action

See docs about how jobs that are skipped still report "success", which
is necessary for jobs that are required to succeed based on branch
protection rules.

https://docs.github.com/en/actions/using-jobs/using-conditions-to-control-job-execution

.github/workflows/nodejs.yml

@@ -1,32 +1,35 @@
 ---
 name: Node CI
 
-on:
-  push:
-    paths-ignore:
-      - '**/*.md'
-      - '**/*.asciidoc'
-      - '**/*.txt'
-      - 'docs/**'
-      - '.ci/**'
-      - '.buildkite/**'
-      - 'scripts/**'
-      - 'catalog-info.yaml'
-  pull_request:
-    paths-ignore:
-      - '**/*.md'
-      - '**/*.asciidoc'
-      - '**/*.txt'
-      - 'docs/**'
-      - '.ci/**'
-      - '.buildkite/**'
-      - 'scripts/**'
-      - 'catalog-info.yaml'
+on: [push, pull_request]
 
 jobs:
+  paths-filter:
+    name: Detect files changed
+    runs-on: ubuntu-latest
+    outputs:
+      skip: '${{ steps.changes.outputs.skip }}'
+    steps:
+      - uses: dorny/paths-filter/@v2.11.1
+        id: changes
+        with:
+          filters: |
+            skip:
+              - '**/*.md'
+              - '**/*.asciidoc'
+              - '**/*.txt'
+              - 'docs/**'
+              - '.ci/**'
+              - '.buildkite/**'
+              - 'scripts/**'
+              - 'catalog-info.yaml'
+
   test:
     name: Test
     runs-on: ${{ matrix.os }}
+    needs: paths-filter
+    # only run if files not in `skip` filter were changed
+    if: needs.paths-filter.outputs.skip != 'true'
 
     strategy:
       fail-fast: false