[check.yml] Update checkout action to v3

tkoeppe · tkoeppe · commit a1dc8ddcebee · 2022-12-19T18:07:34.000Z
diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
@@ -22,7 +22,7 @@ jobs:
 
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: install GNU tools
         if: matrix.cfg.os == 'macos-12'
