Remove kotlin option jvmTarget = "1.8"

Not longer needed since we're on Java 11.

Signed-off-by: Tim Krüger <t@timkrueger.me>

app/build.gradle

@@ -338,9 +338,3 @@ detekt {
     config = files("../detekt.yml")
     input = files("src/")
 }
-
-tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
-    kotlinOptions {
-        jvmTarget = "1.8"
-    }
-}