fix(build): pin error-prone to stable version to resolve CI compilation failure

Downgrade error-prone from 2.48.0 to 2.39.0 to fix a CI-only
compilation crash caused by incompatible transitive dependencies
(e.g. dataflow-errorprone) and javac internals.

The issue manifested as a ServiceLoader/ClassLoader failure during
javac plugin initialization on GitHub Actions, while builds worked
locally due to different JDK/runtime combinations

Author: spannm

pom.xml

@@ -103,7 +103,7 @@
 		<dep.plugin.coveralls.version>4.3.0</dep.plugin.coveralls.version>
 		<dep.plugin.deploy.version>3.1.4</dep.plugin.deploy.version>
 		<dep.plugin.enforcer.version>3.6.2</dep.plugin.enforcer.version>
-		<dep.plugin.error-prone.version>2.48.0</dep.plugin.error-prone.version>
+		<dep.plugin.error-prone.version>2.39.0</dep.plugin.error-prone.version>
 		<dep.plugin.flatten.version>1.7.3</dep.plugin.flatten.version>
 		<dep.plugin.gmavenplus.version>4.3.1</dep.plugin.gmavenplus.version>
 		<dep.plugin.gpg.version>3.2.8</dep.plugin.gpg.version>