docs: add checkout to readme example [skip ci]

aminya · web-flow · commit 6f2162a5a9b5 · 2022-01-22T16:56:54.000-08:00
diff --git a/README.md b/README.md
@@ -136,6 +136,7 @@ jobs:
           - os: "windows-latest"
             compiler: "msvc"
     steps:
+      - uses: actions/checkout@v2
       - name: Cache
         uses: actions/cache@v2
         with:
