Check it still builds after cargo-update

.github/workflows/tests.yml

@@ -44,9 +44,7 @@ jobs:
       matrix:
         os: [macOS-latest, ubuntu-latest, windows-latest]
         version: [stable, nightly, "1.74"]
-
     runs-on: ${{ matrix.os }}
-
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
@@ -68,6 +66,8 @@ jobs:
         run: cargo build --all-targets
       - name: Test
         run: cargo test --workspace
+      - run: cargo update
+      - run: cargo build --all-targets
 
   # Install from a checkout of the source, to find broken dependencies etc.
   # We run this on various versions because some dependencies might have changed