Update contributor doc reflecting #33954

Author: Abacn

contributor-docs/code-change-guide.md

@@ -395,6 +395,8 @@ Follow these steps for Gradle projects.
 
     ```groovy
     repositories {
+    mavenCentral()
+    mavenLocal()
     maven { url "https://repository.apache.org/content/groups/snapshots" }
     }
     ```
@@ -428,18 +430,13 @@ If you're using Dataflow Runner v2 and `sdks/java/harness` or its dependencies (
 1. Use the following command to build the SDK harness container:
 
     ```shell
-    ./gradlew :sdks:java:container:java11:docker # java8, java11, java17, etc
-    # change version number to the actual tag below
-    docker tag apache/beam_java8_sdk:2.64.0.dev \
-      "us.gcr.io/apache-beam-testing/beam_java11_sdk:2.64.0-custom"  # change to your container registry
-    docker push "us.gcr.io/apache-beam-testing/beam_java11_sdk:2.64.0-custom"
+    ./gradlew :sdks:java:harness:publishToMavenLocal -pPublishing
     ```
 
 2. Run the pipeline with the following options:
 
     ```
-    --experiments=use_runner_v2 \
-    --sdkContainerImage="us.gcr.io/apache-beam-testing/beam_java11_sdk:2.49.0-custom"
+    --experiments=use_runner_v2,use_staged_dataflow_worker_jar
     ```
 
 #### Snapshot Version Containers