add missing min/max to BoardConfigurationColumn

[brenol]

Description

Please describe what does this Pull Request fix or add?.

Information that is useful here:

• The What: What is your change doing?
  Fixing missing fields in BoardConfigurationColumn struct.

• The Why: Why is your change useful/needed? What is your use case? (this helps us to understand the real world better)
  So we can identify what is the min/max of a column and to complete the API implementation 👍
  Doc URL: https://developer.atlassian.com/cloud/jira/software/rest/api-group-board/#api-agile-1-0-board-boardid-configuration-get

Doc pic:

• Type of change: Things like Bugfix, New feature, Code quality improvements, Dependency upgrade, Documentation, ...
  I think it's a new feature, but its also a bug fix, so I labeled the commit as a feature.

• Breaking change: Yes or no? Backward compatible?
  Backwards compatible

• Related to an issue: Does this fix or close an issue? Or is related in any kind?
  Did not find any issue

• Jira Version + Type: Which Jira version and type (on-premise / cloud) you have used?
  Unfortunately I'm not sure.

Example:

Let us know how users can use or test this functionality.

// Example code
id := 26
boardConf, _, err := jira.Board.GetBoardConfiguration(id)
if err != nil { 
    panic(err)
}
// assuming your board has columns...
log.Println(boardConf.ColumnConfig.Columns[0].Min)
log.Println(boardConf.ColumnConfig.Columns[0].Max)

Checklist

• Unit or Integration tests added
  • Good Path
  • Error Path
• Commits follow conventions described here:
  • Conventional Commits 1.0.0
  • The seven rules of a great Git commit message
• Commits are squashed such that
  • There is 1 commit per isolated change
• I've not made extraneous commits/changes that are unrelated to my change.

[benjivesterby]

Please add the omitempty tag to the json config for these new fields as well as tests with omitted min/max

[brenol]

Thank you for the quick reply! Made the changes. 😀

[andygrunwald]

Thanks @brenol (and @benjivesterby for the review!)