Forgot a comma

Author: Ciel-MC

gradle.properties

@@ -12,7 +12,7 @@ pluginUntilBuild = 213.*
 
 # Plugin Verifier integration -> https://github.com/JetBrains/gradle-intellij-plugin#plugin-verifier-dsl
 # See https://jb.gg/intellij-platform-builds-list for available build versions.
-pluginVerifierIdeVersions = 2020.2.4, 2020.3.4, 2021.1.1, 2021.2 2021.3
+pluginVerifierIdeVersions = 2020.2.4, 2020.3.4, 2021.1.1, 2021.2, 2021.3
 
 platformType = IC
 platformVersion = 2021.3