chore: rework stable Rust support

.github/workflows/ci.yml

@@ -37,24 +37,52 @@ jobs:
     name: Check
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
+      - name: Delete rust-toolchain.toml
+        run: rm rust-toolchain.toml
+      - name: Install toolchain
+        run: rustup toolchain install --component rustfmt,clippy nightly
       - uses: Swatinem/rust-cache@v2
       - uses: taiki-e/install-action@v2
         with:
           tool: typos-cli,taplo-cli,hawkeye
-      - name: Check stable Rust compatibility
-        run: cargo +stable check --workspace --all-targets
       - run: cargo x lint
 
+  msrv:
+    name: Resolve MSRV
+    runs-on: ubuntu-24.04
+    outputs:
+      rust-versions: ${{ steps.metadata.outputs.rust-versions }}
+    steps:
+      - uses: actions/checkout@v7
+      - id: metadata
+        run: |
+          msrv=$(yq '.workspace.package.rust-version' Cargo.toml)
+          echo "MSRV: $msrv"
+          echo "rust-versions=[\"${msrv}\", \"stable\"]" >> "$GITHUB_OUTPUT"
+
   test:
     name: Run tests
+    needs: msrv
     strategy:
       matrix:
         os: [ ubuntu-24.04, macos-14, windows-2022 ]
+        rust-version: ${{ fromJson(needs.msrv.outputs.rust-versions) }}
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
+      - name: Delete rust-toolchain.toml
+        run: rm rust-toolchain.toml
+      - name: Install toolchain
+        run: |
+          rustup toolchain install ${{ matrix.rust-version }}
+          rustup default ${{ matrix.rust-version }}
       - uses: Swatinem/rust-cache@v2
+        with:
+          cache-bin: "false"
+      - name: Run checks
+        run: cargo x check
+        shell: bash
       - name: Run unit tests
         run: cargo x test --no-capture
         shell: bash