Update GitHub Actions to use checkout@v4

Author: Antynea

.github/workflows/bump-version.yml

@@ -14,19 +14,18 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           ref: master
 
       - name: Update version in config
         run: |
-          version="${{ github.ref_name }}"
-          sed -i "s/GRUB_BTRFS_VERSION=.*/GRUB_BTRFS_VERSION=${version}/" config
+          sed -i "s/GRUB_BTRFS_VERSION=.*/GRUB_BTRFS_VERSION=${{ github.ref_name }}/" config
 
       - name: Commit updated config
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"
           git add config
-          git commit -m "chore: bump version to ${version}"
+          git commit -m "chore: bump version to ${{ github.ref_name }}"
           git push origin master