Switch CI toolchain action to dtolnay/rust-toolchain

There were recently a lot of hiccups with installing rustup for Windows
in CI and the previously used actions from actions-rs seem to be no
longer maintained. Following the discussion in
rust-lang/rustup#3409, this is one way to go.

.github/workflows/build.yaml

@@ -78,27 +78,19 @@ jobs:
         uses: actions/checkout@v2
 
       - name: Build | install toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
           target: ${{ inputs.target }}
           toolchain: ${{ inputs.toolchain }}
-          default: true
 
       - name: Build | rust-cache
         uses: Swatinem/rust-cache@v1
 
       - name: Build | build library (default features)
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --target=${{ inputs.target }}
+        run: cargo build --target=${{ inputs.target }}
 
       - name: Build | build library (all features)
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --all-features --target=${{ inputs.target }}
+        run: cargo build --all-features --target=${{ inputs.target }}
 
       - name: Build | build examples (default features)
         if: ${{ inputs.disable_extra_builds == false }}

.github/workflows/ci.yaml

@@ -29,27 +29,19 @@ jobs:
         uses: actions/checkout@v2
 
       - name: Lint | install toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
           toolchain: stable
-          default: true
           components: clippy, rustfmt
 
       - name: Lint | rust-cache
         uses: Swatinem/rust-cache@v1
 
       - name: Lint | check formatting
-        uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: -- --check
+        run: cargo fmt -- --check
 
       - name: Lint | clippy
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --all-targets --all-features
+        run: cargo clippy --all-targets --all-features
 
   # --------------------------------------------------------------------------
   # MSRV