Update django-tables2 to 1.2.3

[pyup-bot]

There's a new version of django-tables2 available.
You are currently using 1.2.1. I have updated it to 1.2.3

Changelog

1.2.3

• Accept text parameter in FileColumn, analogous to LinkColumn (343 by graup)
• Fix TemplateColumn RemovedInDjango110Warning fixes 346.
• Use field name in RelatedColumnLink (350, fixes 347

1.2.2

• Allow use of custom class names for ordered columns through attrs. (
  329 by theTarkus)
• Column ordering queryset passthrough (330 by theTarkus)
• Cleanup/restructuring of documentation, (325
• Fixed an issue where explicitly defined column options where not preserved over inheritance (339, issue 337)
• Fixed an issue where exclude in combination with sequence raised a KeyError (341, issue 205)

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖