Bump actions/checkout from 2 to 3 (#20)

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

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
       matrix:
         rust: [nightly, beta, stable]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{matrix.rust}}
@@ -27,7 +27,7 @@ jobs:
     name: Rust 1.36.0
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: dtolnay/[email protected]
       - run: cargo build
       - run: cargo build --features small
@@ -36,7 +36,7 @@ jobs:
     name: Miri
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@nightly
         with:
           components: miri
@@ -49,7 +49,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name != 'pull_request'
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@clippy
       - run: cargo clippy --tests --benches -- -Dclippy::all -Dclippy::pedantic
 
@@ -58,6 +58,6 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name != 'pull_request'
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: dtolnay/install@cargo-outdated
       - run: cargo outdated --exit-code 1