Update dependencies

* gradle-intellij-plugin to 1.1.3
* JVM to 11

With these changes, the way other settings are described has changed slightly.

* JetBrains/intellij-platform-gradle-plugin#703

gradle-intellij-plugin from v1.1.4 or above (at least to v1.1.6) has a bug.

* JetBrains/intellij-platform-gradle-plugin#752

build.gradle

@@ -9,15 +9,19 @@ buildscript {
 
 plugins {
     id 'java'
-    id 'org.jetbrains.intellij' version '0.4.8'
+    id 'org.jetbrains.intellij' version '1.1.3'
 }
 
 apply plugin: 'kotlin'
 
 group 'io.github.takc923'
 version '0.3-SNAPSHOT'
 
-sourceCompatibility = 1.8
+sourceCompatibility = 11
+
+compileKotlin {
+    kotlinOptions.jvmTarget = "11"
+}
 
 repositories {
     mavenCentral()
@@ -29,10 +33,11 @@ dependencies {
 
 intellij {
     version '2021.1'
-    updateSinceUntilBuild false
+    updateSinceUntilBuild = false
 }
+
 patchPluginXml {
-    changeNotes """
+    changeNotes = """
 <p>v0.2</p>
 <ul>
   <li>Update kotlin and supported intellij version</li>
@@ -42,4 +47,4 @@ patchPluginXml {
   <li>Initial release</li>
 </ul>
 """
-}
+}