Removed upToDateWhen of copyLicense task

This was originally added because the task was also responsible for
copying the current git commit hash to the "about" screen.
The commit was later moved to a `buildConfigField`,
so this can now be removed again.

app/build.gradle

@@ -206,7 +206,6 @@ task copyLicense(type: Copy) {
     rename { String fileName ->
         fileName + ".txt"
     }
-    outputs.upToDateWhen { false }
 }
 
 preBuild.dependsOn copyLicense