Test build with minimal versions from CI

.github/workflows/tests.yml

@@ -69,6 +69,15 @@ jobs:
       - run: cargo update
       - run: cargo build --all-targets
 
+  build-minimal-versions:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+      - uses: Swatinem/rust-cache@v2
+      - run: cargo +nightly -Zdirect-minimal-versions 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
   # their MSRV, and on every platform because there are platform-specific