chore(ci): only run cargo check on MSRV, not tests

.github/workflows/CI.yml

@@ -15,6 +15,7 @@ jobs:
     needs:
       - style
       - test
+      - msrv
       - features
       - ffi
       - ffi-header
@@ -52,7 +53,6 @@ jobs:
           - stable
           - beta
           - nightly
-          - 1.46 # keep in sync with MSRV.md dev doc
 
         os:
           - ubuntu-latest
@@ -67,8 +67,6 @@ jobs:
           - rust: nightly
             features: "--features full,nightly"
             benches: true
-          - rust: 1.46
-            features: "--features full"
 
     runs-on: ${{ matrix.os }}
 
@@ -96,6 +94,36 @@ jobs:
           command: test
           args: --benches ${{ matrix.features }}
 
+  msrv:
+    name: Check MSRV (${{ matrix.rust }})
+    needs: [style]
+    strategy:
+      matrix:
+        rust:
+          - 1.46 # keep in sync with MSRV.md dev doc
+
+        os:
+          - ubuntu-latest
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+
+      - name: Install Rust (${{ matrix.rust }})
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          override: true
+
+      - name: Check
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+          args: --features full
+
   features:
     name: features
     needs: [style]