Bump versionCode. (#6104)

Author: Williamrai

app/build.gradle

@@ -40,7 +40,7 @@ android {
  applicationId 'org.wikipedia'
  minSdk = 23
  targetSdk = 36
- versionCode 50555
+ versionCode 50556
  testApplicationId 'org.wikipedia.test'
  testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
  testInstrumentationRunnerArguments clearPackageData: 'true'