Update actions/checkout action to v4 (#140)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/release.yaml

@@ -9,7 +9,7 @@ jobs:
   goreleaser:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - run: |
           git fetch --prune --unshallow
       - name: Generate version

.github/workflows/unit-tests.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Install Go

.github/workflows/webui.yaml

@@ -12,7 +12,7 @@ jobs:
   webui:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install earthly
         uses: Luet-lab/luet-install-action@v1
         with: