Bump actions/checkout from 3 to 4 (#455)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/main.yaml

@@ -20,7 +20,7 @@ jobs:
         scala-version: ["2.12", "2.13", "3"]
         target-platform: ["JVM", "JS"]
     steps:
-      - uses: actions/checkout@v3.5.3
+      - uses: actions/checkout@v4
       - uses: coursier/[email protected]
       - name: Set up JDK 11
         uses: actions/setup-java@v3
@@ -56,7 +56,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0 # checkout tags so that dynver works properly (we need the version for MiMa)
       - name: Set up JDK 11
@@ -74,7 +74,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0 # checkout tags so that dynver works properly (we need the version for MiMa)
       - name: Set up JDK 11
@@ -92,7 +92,7 @@ jobs:
     needs: [build]
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v3.5.3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - uses: coursier/[email protected]

.github/workflows/scala-steward.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v3.5.3
+        uses: actions/checkout@v4
       - name: Set up JDK 11
         uses: actions/setup-java@v3
         with: