CI: build with MSRV & stable and test features

this creates a build matrix which tests with both the MSRV and the
stable rust release and also tests both with the default features and
all features selected.

Author: rursprung

.github/workflows/CI.yml

@@ -10,27 +10,40 @@ env:
 
 jobs:
   build:
+    strategy:
+      fail-fast: false
+      matrix:
+        rust: [1.60.0, stable]
+        features: ['', '--all-features']
 
     runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.rust }}
+          components: rustfmt clippy
       - 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 
+          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
         with:
           command: audit