Upgrade to JDK 16, Kotlin 1.3.21 and Gradle 7.1.1

.idea/akismet-kotlin.iml

@@ -1,2 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<module type="JAVA_MODULE" version="4" />

.idea/compiler.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <bytecodeTargetLevel target="1.8" />
+  </component>
+</project>

.idea/jarRepositories.xml

@@ -26,5 +26,15 @@
       <option name="name" value="MavenLocal" />
       <option name="url" value="file:$MAVEN_REPOSITORY$/" />
     </remote-repository>
+    <remote-repository>
+      <option name="id" value="MavenRepo" />
+      <option name="name" value="MavenRepo" />
+      <option name="url" value="https://repo.maven.apache.org/maven2/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="maven" />
+      <option name="name" value="maven" />
+      <option name="url" value="https://oss.sonatype.org/content/repositories/snapshots" />
+    </remote-repository>
   </component>
 </project>

.idea/misc.xml

@@ -12,7 +12,7 @@
   <component name="JavaScriptSettings">
     <option name="languageLevel" value="ES6" />
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="false" project-jdk-name="1.8" project-jdk-type="JavaSDK" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="15" project-jdk-type="JavaSDK" />
   <component name="SuppressionsComponent">
     <option name="suppComments" value="[]" />
   </component>