Update GitHub Actions actions/checkout@v2 to v3 (#2595)

The v2 implementation uses Node 12, which is end-of-life on April 30, 2022.
See https://nodejs.org/en/about/releases/. Update to v3, which is based on
Node 16 whose support lasts until April 30, 2024.

Author: dtolnay

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
           - windows-latest
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         # --no-self-update is necessary because the windows environment cannot self-update rustup.exe.
         run: rustup update nightly --no-self-update && rustup default nightly
@@ -53,7 +53,7 @@ jobs:
           - aarch64-unknown-linux-gnu
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - name: Install cross
@@ -73,7 +73,7 @@ jobs:
           - 1.36
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }}
       # cargo does not support for --features/--no-default-features with workspace, so use cargo-hack instead.
@@ -105,7 +105,7 @@ jobs:
           - 1.45
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }}
       - name: Install cargo-hack
@@ -136,7 +136,7 @@ jobs:
           - nightly
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }}
       - name: Install cargo-hack
@@ -148,7 +148,7 @@ jobs:
     name: cargo build -Z minimal-versions
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - name: Install cargo-hack
@@ -170,7 +170,7 @@ jobs:
           - thumbv6m-none-eabi
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - run: rustup target add ${{ matrix.target }}
@@ -202,7 +202,7 @@ jobs:
     name: cargo bench
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - run: cargo bench --workspace
@@ -212,7 +212,7 @@ jobs:
     name: cargo hack check --feature-powerset
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - name: Install cargo-hack
@@ -237,7 +237,7 @@ jobs:
       contents: write
       pull-requests: write
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - run: ci/no_atomic_cas.sh
@@ -270,7 +270,7 @@ jobs:
     name: cargo miri test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup toolchain install nightly --component miri && rustup default nightly
       - run: cargo miri test --workspace --all-features
@@ -289,7 +289,7 @@ jobs:
           - thread
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - run: rustup component add rust-src
@@ -304,7 +304,7 @@ jobs:
     name: cargo clippy
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup toolchain install nightly --component clippy && rustup default nightly
       - run: cargo clippy --workspace --all-features --all-targets
@@ -313,7 +313,7 @@ jobs:
     name: cargo 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
@@ -322,7 +322,7 @@ jobs:
     name: cargo doc
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install Rust
         run: rustup update nightly && rustup default nightly
       - run: RUSTDOCFLAGS="-D warnings --cfg docsrs" cargo doc --workspace --no-deps --all-features