github: New checkout@v3

Author: wsnyder

.github/workflows/build.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
 # This uses the ":stable" version of Verilator, you may prefer ":latest"
 # We run make from inside the container, overriding default entry point (Verilator binary itself)