Upgrade to checkout v3

Signed-off-by: utam0k <[email protected]>

Author: utam0k

.github/workflows/build.yaml

@@ -22,7 +22,7 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           # By default, the checkout action only fetches the last commit,
           # but we want to run DCO check against all commit messages.