newbie issue: building 3.3.0

hi,

i'm trying to build 3.3.0 and i get the following error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.17:check (validate) on project rest-utils-parent: Execution validate of goal org.apache.maven.plugins:maven-checkstyle-plugin:2.17:check failed: Plugin org.apache.maven.plugins:maven-checkstyle-plugin:2.17 or one of its dependencies could not be resolved: Could not find artifact io.confluent:build-tools:jar:3.3.0 in central (https://repo.maven.apache.org/maven2) -> [Help 1]

i'm using the following dockerfile, any suggestions?

```
FROM maven:latest

ENV CONFLUENT_VERSION v3.3.0

RUN mkdir -p /usr/src/ && \
cd /usr/src/ && \
git clone --branch ${CONFLUENT_VERSION} https://github.com/confluentinc/common && \
cd common && \
mvn -Dmaven.test.skip=true clean install

RUN cd /usr/src/common/parent && \
git clone --branch ${CONFLUENT_VERSION} https://github.com/confluentinc/rest-utils && \
cd rest-utils && \
mvn -Dmaven.test.skip=true clean install
```

Start with the Dockerfile commands that clone the v3.3.0 branches and run Maven, then inspect why io.confluent:build-tools:jar:3.3.0 is not resolved from Maven Central. Reproduce the failure with the supplied Dockerfile and confirm that the v3.3.0 build completes successfully.

Written by the indexing model from the issue text.