Guidance for filling out "Affects Version" on Jira

[Nicholas Chammas <ni...@gmail.com>]

The Contributing guide <https://spark.apache.org/contributing.html> only mentions what to fill in for “Affects Version” for bugs. How about for improvements?

This question once caused some problems when I set “Affects Version” to the last released version, and that was interpreted as a request to backport an improvement, which was not my intention and caused a minor kerfuffle.

Could we provide some clarity on the Contributing guide on how to fill in this field for improvements, especially since “Affects Version” is required on all Jira tickets?

Nick