Fix CI: cargo doc --lock (RustPython#6888)

* cargo doc --locked

* Update Cargo.lock

Author: youknowone

.github/workflows/ci.yaml

@@ -450,7 +450,7 @@ jobs:
         run: cargo clippy --manifest-path=crates/wasm/Cargo.toml -- -Dwarnings
 
       - name: Ensure docs generate no warnings
-        run: cargo doc
+        run: cargo doc --locked
 
       - name: Ensure Lib/_opcode_metadata is updated
         run: |