updated readme to use updated action checkout version

StephenHodgson · StephenHodgson · commit a04be423fa6c · 2022-11-02T02:01:25.000-04:00
diff --git a/README.md b/README.md
@@ -38,7 +38,7 @@ jobs:
             build-target: StandaloneLinux64
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           submodules: recursive
           clean: true
