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](https://github.com/actions/checkout/compare/v2...v3)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/rust.yml

@@ -23,7 +23,7 @@ jobs:
       matrix:
         os: [ubuntu-18.04, macos-latest, windows-latest]
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Cache dependencies
       uses: Swatinem/rust-cache@v1.3.0
     - name: Run cargo check without any default features
@@ -42,7 +42,7 @@ jobs:
     name: Run tests in debug
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -60,7 +60,7 @@ jobs:
     name: Run Clippy
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -79,7 +79,7 @@ jobs:
     name: Run Rustfmt
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal