Change version to 500.0, and the untilBuild to 253.* (#79)

These changes are anticipation of landing the Dart Plugin in coming days from the Google vendor.

Author: jwren

third_party/gradle.properties

@@ -7,15 +7,15 @@ pluginName = Dart
 pluginId = Dart
 
 # SemVer format -> https://semver.org
-pluginVersion = 89.0
+pluginVersion = 500.0
 
 # TODO(https://github.com/flutter/dart-intellij-third-party/issues/23) Add a changelog
 # Not currently used in the build.gradle.kts file:
 # pluginRepositoryUrl = https://github.com/flutter/dart-intellij-third-party
 
 # Supported build number ranges and IntelliJ Platform versions -> https://plugins.jetbrains.com/docs/intellij/build-number-ranges.html
 pluginSinceBuild = 251
-pluginUntilBuild = 251.*
+pluginUntilBuild = 253.*
 
 # Gradle Releases -> https://github.com/gradle/gradle/releases
 gradleVersion = 8.13