ci: migrate from dtolnay/rust-toolchain to actions-rust-lang/setup-rust-toolchain

- Proper semver tags (v1.15.4) allow Dependabot to update SHA pins
- Built-in cache removes the need for separate actions/cache steps
- rustflags: "" disables the default -D warnings behavior

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: 23prime

.github/workflows/check-rust.yml

@@ -27,20 +27,10 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7 # stable
+        uses: actions-rust-lang/setup-rust-toolchain@150fca883cd4034361b621bd4e6a9d34e5143606 # v1.15.4
         with:
           components: rustfmt, clippy
-
-      - name: Cache cargo registry
-        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-            target
-          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-
+          rustflags: ""
 
       - name: Install mise
         uses: jdx/mise-action@1648a7812b9aeae629881980618f079932869151 # v4.0.1
@@ -64,18 +54,7 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7 # stable
-
-      - name: Cache cargo registry
-        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-            target
-          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-
+        uses: actions-rust-lang/setup-rust-toolchain@150fca883cd4034361b621bd4e6a9d34e5143606 # v1.15.4
 
       - name: Check
         run: cargo check --locked

.github/workflows/release.yml

@@ -57,20 +57,10 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Install Rust
-        uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7 # stable
+        uses: actions-rust-lang/setup-rust-toolchain@150fca883cd4034361b621bd4e6a9d34e5143606 # v1.15.4
         with:
-          targets: ${{ matrix.target }}
-
-      - name: Cache cargo registry
-        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-            target
-          key: ${{ runner.os }}-${{ matrix.target }}-cargo-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-${{ matrix.target }}-cargo-
+          target: ${{ matrix.target }}
+          rustflags: ""
 
       - name: Install cross
         if: matrix.use_cross