ci: add turbo cache (#4)

.github/workflows/ci.yml

@@ -1,21 +1,31 @@
 name: CI
 
 on:
+  push:
+    branches: [main]
   pull_request:
     branches: [main]
+    types: [opened, synchronize]
 
 jobs:
   test:
+    timeout-minutes: 15
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest]
         node-version: [18.x]
-
     runs-on: ${{ matrix.os }}
 
     steps:
       - uses: actions/checkout@v4
 
+      - uses: actions/cache@v3
+        with:
+          path: node_modules/.cache/turbo
+          key: ${{ runner.os }}-turbo-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-turbo-
+
       - uses: pnpm/action-setup@v2
 
       - uses: actions/setup-node@v4