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/dotnet-core.yml

@@ -15,7 +15,7 @@ jobs:
     name: Build Single-File Artifact
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/[email protected]
         with:
           dotnet-version: 6.x
@@ -56,7 +56,7 @@ jobs:
     name: Build - Windows .NET Framework Zip
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/[email protected]
         with:
           dotnet-version: 6.x
@@ -75,7 +75,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.repository == 'SamboyCoding/Cpp2IL'
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/[email protected]
         with:
           dotnet-version: 6.x