Fix bootstrap kotlin plugin version
diff --git a/gradle.properties b/gradle.properties
index 9dea2b2..3f08ada 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -8,7 +8,7 @@
 #maven.repository.mirror=http://repository.jetbrains.com/remote-repos/
 #bootstrap.kotlin.repo=https://dl.bintray.com/kotlin/kotlin-dev
 #bootstrap.kotlin.version=1.1.50-dev-1451
-bootstrap.kotlin.default.version=1.4.0-dev-9619
+bootstrap.kotlin.default.version=1.4.20-dev-117
 
 #signingRequired=true