fix: don't restrict serde to 1.0.152 in CI

Author: sander2

.github/workflows/rust.yml

@@ -27,7 +27,7 @@ jobs:
                   profile: minimal
                   toolchain: ${{ matrix.rust }}
                   override: true
-            - run: cargo update -p serde --precise 1.0.152
+            - run: cargo update -p serde
             - name: Running test script
               env: ${{ matrix.env }}
               run: ./contrib/test.sh