Fix rust 1.45 CI

.github/workflows/ci.yml

@@ -36,6 +36,9 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.rust }}
           override: true          
+      - if: matrix.rust == '1.45.0'
+        # work-around https://github.com/serde-rs/serde/issues/2255
+        run: cargo update -p serde --precise 1.0.142
       - name: Check with no feature flags
         run: cargo check --verbose --no-default-features
         continue-on-error: ${{ matrix.allow_failure }}