CI: correctly test against MSRV, remove outdated actions

so far the rust attribute of the build matrix had been ignored, which
was incorrect.

see actions-rs/toolchain#216 for more information on the outdated
actions.

Author: rursprung

.github/workflows/CI.yml

@@ -14,31 +14,24 @@ jobs:
       fail-fast: false
       matrix:
         rust: [1.65.0, stable]
-        features: ['', '--features rgb,serde']
-
+        features: ['', '--all-features']
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: ${{ matrix.features }}
-      - uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: ${{ matrix.features }}
-      - uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: ${{ matrix.features }}
-      - uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
-      - uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: ${{ matrix.features }}
-      - uses: actions-rs/cargo@v1
+      - name: install rust toolchain
+        uses: dtolnay/rust-toolchain@master
         with:
-          command: audit
+          toolchain: ${{ matrix.rust }}
+          components: rustfmt clippy
+      - name: build
+        run: cargo build ${{ matrix.features }}
+      - name: check
+        run: cargo check ${{ matrix.features }}
+      - name: test
+        run: cargo test ${{ matrix.features }}
+      - name: check formatting
+        run: cargo fmt --all -- --check
+      - name: clippy
+        run: cargo clippy ${{ matrix.features }}
+      - name: audit
+        run: cargo audit