update action versions in docs

Author: nicktrn

docs/github-actions.mdx

@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Use Node.js 20.x
         uses: actions/setup-node@v4
@@ -56,7 +56,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Use Node.js 20.x
         uses: actions/setup-node@v4