Silence a warning

app/build.gradle

@@ -172,5 +172,4 @@ dependencies {
 configurations.all {
     exclude group: 'dev.rikka.rikkax.appcompat', module: 'appcompat'
     exclude group: 'dev.rikka.rikkax.material', module: 'material'
-    exclude group: 'org.jetbrains.kotlin', module: 'kotlin-stdlib-jdk7'
 }