Auto merge of #611 - jrmuizel:msrv, r=mstange

Add MSRV check to CI

None

Author: bors-servo

.github/workflows/rust.yml

@@ -16,6 +16,17 @@ jobs:
     - uses: actions/checkout@v2
     - name: Check semver
       uses: obi1kenobi/cargo-semver-checks-action@v2
+  msrv:
+    runs-on: macos-11.0
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install toolchain
+      uses: actions-rs/toolchain@v1
+      with:
+        toolchain: 1.56.1
+        override: true
+    - name: Build
+      run: cargo build --verbose
   build:
     runs-on: ${{ matrix.os }}
     strategy: