Use actions/checkout@v3

This avoids a deprecation warning from GitHub relating to Node 12.

Author: kulp

.github/workflows/c.yml

@@ -22,7 +22,7 @@ jobs:
     - run: brew install bison expect icarus-verilog lcov
     - if: env.SDL != 0
       run: brew install sdl2 sdl2_image
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         submodules: true
     - run: |
@@ -53,7 +53,7 @@ jobs:
     - if: env.SDL != 0
       run: |
         brew install sdl2 sdl2_image
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         submodules: true
     - if: env.JIT != 0