chore: don't check examples on MSRV

.github/workflows/CI.yml

@@ -24,7 +24,7 @@ jobs:
       uses: actions-rs/cargo@v1
       with:
         command: check
-        args: --all --bins --examples --tests --benches
+        args: --all --bins --tests --benches
 
   cargo-hack:
     runs-on: ubuntu-latest
@@ -114,7 +114,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rust: [stable, beta, nightly, 1.42.0]
+        rust: [stable, beta, nightly]
     steps:
     - uses: actions/checkout@main
     - uses: actions-rs/toolchain@v1
@@ -128,6 +128,32 @@ jobs:
         command: test
         args: --all
 
+  test-msrv:
+    # Test against the minimum supported Rust version
+    needs: check
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@main
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: 1.42.0
+        profile: minimal
+        override: true
+    # We can't use `cargo test --all`, as that will also compile the examples.
+    # We don't guarantee the examples will work on the MSRV, because they have
+    # external dependencies which may not comply with our MSRV policy, but don't
+    # actually impact users on our MSRV.
+    - name: Run tests
+      uses: actions-rs/cargo@v1
+      with:
+        command: test
+        args: --workspace --lib --tests
+    - name: Run doctests
+      uses: actions-rs/cargo@v1
+      with:
+        command: test
+        args: --workspace --doc
+
   test-build-wasm:
     needs: check
     runs-on: ubuntu-latest