Android Kotlin Fundamentals codelab: Outdated information about android version number

[Arthur-Milchior]

Name of the Codelab or Codelab URL

https://developer.android.com/codelabs/kotlin-android-training-images-compat#5 task 6 step 1

Describe the problem
"The Android OS has different version numbers named after tasty treats which are in alphabetical order. " should be changed to indicate that it was the case up to L/LOLLIPOP, after which a single letter, potentially followed by _MR1 or _V2, is used.

codelab: android-kotlin-fundamentals