ZetaSQL Toolkit v0.5.1

Changelog:

• Avoid NullPointerException when quoting name paths of an unnest expression (#52)
  • Closes #51

Dependency updates

• com.google.cloud:libraries-bom from 26.37.0 to 26.39.0
• com.google.cloud.tools:jib-maven-plugin from 3.3.2 to 3.4.2

Plugin updates

• org.apache.maven.plugins:maven-jar-plugin from 3.3.0 to 3.4.1
• org.apache.maven.plugins:maven-source-plugin from 3.3.0 to 3.3.1
• org.apache.maven.plugins:maven-javadoc-plugin from 3.5.0 to 3.6.3
• org.apache.maven.plugins:maven-surefire-plugin from 3.1.0 to 3.2.5
• org.apache.maven.plugins:maven-gpg-plugin from 3.1.0 to 3.2.4
• org.codehaus.mojo:properties-maven-plugin from 1.1.0 to 1.2.1