chore(gradle): update plugin version to 1.6.4

Update plugin version to 1.6.4 in `gradle.properties` file. This ensures the correct version is used for the AutoDev plugin.

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 = 1.6.4-SNAPSHOT
+pluginVersion = 1.6.4
 
 # Supported IDEs: idea, pycharm
 baseIDE=idea