ci: Update to actions/checkout@v4 from v3.

Author: waywardmonkeys

.github/workflows/cmake.yml

@@ -24,7 +24,7 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - if: ${{ matrix.install-deps }}
       name: Install dependencies