Add a delay to starting Docker for integration tests

Give the Docker container a bit more time to start up so we don't get
spurious failures.

.github/workflows/validation-rust.yaml

@@ -114,6 +114,9 @@ jobs:
           -e RUST_LIB_BACKTRACE=1
           --name mdb-example-container
           mdb-example-so
+          && sleep 4
+        # verify we started successfully
+      - run: mysql -uroot -pexample -h0.0.0.0 -P12300 --protocol=tcp -e 'show databases'
       - name: Run integration testing
         # Run only integration tests with `--test '*'`
         run: cargo test -p udf-examples --test '*' --features backend

Dockerfile.examples

@@ -26,6 +26,6 @@ RUN --mount=type=cache,target=/usr/local/cargo/registry \
     && mkdir /output \
     && cp target/release/libudf_examples.so /output
 
-FROM mariadb:10.10
+FROM mariadb:11.3
 
 COPY --from=build /output/* /usr/lib/mysql/plugin/