Bumped version of kotlin-compiler to 1.3.20 in ktlint-ruleset-template

Author: Stanley Shyiko

ktlint-ruleset-template/build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-    ext.kotlin_version = '1.3.10'
+    ext.kotlin_version = '1.3.20'
     repositories {
         mavenCentral()
         maven { url 'http://repo.spring.io/plugins-release' }