Android: Upgrade Kotlin to 1.6.20

android/app/src/main/java/io/github/kichikuou/system3/Launcher.kt

@@ -234,7 +234,7 @@ class Launcher private constructor(private val rootDir: File) {
         fun maybeAdd(path: String) {
             val name = File(path).name
 
-            if (name.toLowerCase(Locale.US) == "adisk.dat") {
+            if (name.lowercase(Locale.US) == "adisk.dat") {
                 hasAdisk = true
             }
             audioRegex.matchEntire(name)?.let {

android/build.gradle

@@ -1,12 +1,13 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.4.32'
+    ext.kotlin_version = '1.6.20'
     repositories {
         mavenCentral()
         google()
     }
     dependencies {
+        // AGP 7.1.x cannot be used due to https://issuetracker.google.com/issues/206099937
         classpath 'com.android.tools.build:gradle:7.0.4'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"