bump compile sdk to 31

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

app/build.gradle

@@ -35,7 +35,7 @@ apply plugin: 'io.gitlab.arturbosch.detekt'
 apply plugin: "org.jlleitschuh.gradle.ktlint"
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 31
     buildToolsVersion '32.0.0'
     defaultConfig {
         minSdkVersion 21