chore(gradle): update plugin version to 2.0.0-alpha.6

Updated the plugin version in `gradle.properties` from 2.0.0-ALPHA5 to 2.0.0-alpha.6 to follow SemVer format

Author: phodal

gradle.properties

@@ -7,7 +7,7 @@ pluginGroup = com.phodal.autodev
 pluginName = AutoDev
 pluginRepositoryUrl = https://github.com/unit-mesh/auto-dev
 # SemVer format -> https://semver.org
-pluginVersion = 2.0.0-ALPHA5
+pluginVersion = 2.0.0-alpha.6
 
 # Supported IDEs: idea, pycharm
 baseIDE=idea