use v4

Author: guzba

.github/workflows/docs.yml

@@ -11,7 +11,7 @@ jobs:
   docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: jiro4989/setup-nim-action@v1
         with:
           nim-version: ${{ env.nim-version }}