Remove dtolnay/rust-toolchain

.github/workflows/rust.yml

@@ -19,9 +19,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
-        with:
-          components: rustfmt
       - uses: DavidAnson/markdownlint-cli2-action@v16
         with:
           globs: "exercises/**/*.md"
@@ -34,7 +31,6 @@ jobs:
         os: [ubuntu-latest, windows-latest, macOS-latest]
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
       - uses: swatinem/rust-cache@v2
       - name: Run cargo test
         run: cargo test

.github/workflows/web.yml

@@ -57,7 +57,6 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - uses: dtolnay/rust-toolchain@stable
       - uses: swatinem/rust-cache@v2
 
       # If you use any mdbook plugins, here's the place to install them!