v0.57.0

⚠️ The spectator-ext-log4j1 extension was incorrectly published with a .md extension.

Primary changes:

• #422, added appender for use with log4j 1.x.
• #425, fix reflective access issue when running on jdk9.
• #433, work queue mappings added for Artifactory.
• #439, added helper for boolean tag values.

A comprehensive list of changes can be found in the commit log: v0.56.0...v0.57.0