Bump actions/checkout from 3 to 4

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]>

.github/workflows/release.yml

@@ -9,7 +9,7 @@ jobs:
   publish:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Scala caches
@@ -56,7 +56,7 @@ jobs:
   scalapbc:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - uses: actions/setup-java@v3
@@ -80,7 +80,7 @@ jobs:
           arch: osx-x86_64
     runs-on: ${{matrix.os}}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - uses: olafurpg/setup-scala@v13
@@ -114,7 +114,7 @@ jobs:
     runs-on: ubuntu-20.04
     needs: [native, scalapbc]
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Download artifacts

.github/workflows/test.yml

@@ -20,7 +20,7 @@ jobs:
           script: scala3_compat_test
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - uses: actions/setup-java@v3
       with:
@@ -46,7 +46,7 @@ jobs:
   conformance:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: actions/cache@v3
       id: conformance-cache
       with: