Update XmlSerializer.php - Support tags

[dzandrey]

Added support for Redmine tags -https://www.redmine.org/plugins/redmineup_tags

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (6a4e464) 97.63% compared to head (05d360b) 97.63%. Report is 42 commits behind head on v2.x.

Additional details and impacted files

@@            Coverage Diff            @@
##               v2.x     #379   +/-   ##
=========================================
  Coverage     97.63%   97.63%           
  Complexity      563      563           
=========================================
  Files            29       29           
  Lines          1609     1610    +1     
=========================================
+ Hits           1571     1572    +1     
  Misses           38       38           

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[Art4]

Thank you for your contribution. This project focuses on the original Redmine server without modifications. Unfortunately, we cannot accept features for proprietary plugins without documentation.

I recommend you to build your own API client for the plugin. You can use this library as a basis for this. If you want to have certain things open or customizable to make it easier to implement support for the plugin, feel free to open an issue and we'll see what we can do.

[Art4]

If you would like to help implementing #380 you are welcome to update this PR.