Bump actions/checkout from 2 to 3

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/dotnet.yml

@@ -14,7 +14,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Setup .NET
       uses: actions/setup-dotnet@v1
       with:
@@ -37,7 +37,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: build 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Setup .NET
       uses: actions/setup-dotnet@v1
       with:
@@ -74,7 +74,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: build 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Setup .NET
       uses: actions/setup-dotnet@v1
       with: