chore(deps): update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/build.yml

@@ -9,7 +9,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Use Node.js
         uses: actions/setup-node@v1
         with:

.github/workflows/pr-auditor.yml

@@ -8,7 +8,7 @@ jobs:
   check-pr:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           repository: 'sourcegraph/pr-auditor'
       - uses: actions/setup-go@v4