lock playground dependencies and enable setup-node's cache feature

instead of using actions/cache by ourselves

Author: rhysd

.github/workflows/ci.yaml

@@ -72,11 +72,8 @@ jobs:
       - uses: actions/setup-node@v5
         with:
           node-version: "lts/*"
-      - name: Cache node_modules
-        uses: actions/cache@v4
-        with:
-          path: ./playground/node_modules
-          key: ${{ hashFiles('./playground/package.json') }}
+          cache: npm
+          cache-dependency-path: ./playground/package-lock.json
       - name: Build playground
         run: make build
       - name: Lint playground

.github/workflows/matcher.yaml

@@ -23,6 +23,8 @@ jobs:
       - uses: actions/setup-node@v5
         with:
           node-version: "lts/*"
+          cache: npm
+          cache-dependency-path: ./playground/package-lock.json
       - name: Update test data
         run: make ./scripts/generate-actionlint-matcher/test/* SKIP_GO_GENERATE=true
       - name: Test actionlint-matcher.json

playground/.gitignore

@@ -1,7 +1,6 @@
 /lib
 /main.wasm
 /node_modules
-/package-lock.json
 /image
 /*.js
 /*.js.map