Update actions/checkout action to v3

Author: taiki-e

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
         os: [ubuntu-latest]
         rust: [nightly, beta, stable]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }}
       - run: rustup target add thumbv7m-none-eabi
@@ -47,31 +47,31 @@ jobs:
         # Rust version in Cargo.toml and .clippy.toml.
         rust: ['1.39']
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }}
       - run: cargo build
 
   clippy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update stable
       - run: cargo clippy --all-features
 
   fmt:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update stable
       - run: cargo fmt --all -- --check
 
   security_audit:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/audit-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/release.yml

@@ -14,7 +14,7 @@ jobs:
     if: github.repository_owner == 'smol-rs'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update stable
       - run: cargo package