Raise minimum compiler for tests to rust 1.70

Author: dtolnay

.github/workflows/ci.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        rust: [nightly, beta, stable, 1.56.0]
+        rust: [nightly, beta, stable, 1.70.0, 1.56.0]
     timeout-minutes: 45
     steps:
       - uses: actions/checkout@v4
@@ -37,7 +37,9 @@ jobs:
       - name: Enable nightly-only tests
         run: echo RUSTFLAGS=${RUSTFLAGS}\ --cfg=async_trait_nightly_testing >> $GITHUB_ENV
         if: matrix.rust == 'nightly'
+      - run: cargo check
       - run: cargo test
+        if: matrix.rust != '1.56.0'
       - uses: actions/upload-artifact@v4
         if: matrix.rust == 'nightly' && always()
         with: