Update django-tables2 to 1.18.0

[pyup-bot]

There's a new version of django-tables2 available.
You are currently using 1.12.0. I have updated it to 1.18.0

These links might come in handy: PyPI | Changelog | Repo

Changelog

1.18.0

• Follow relations when detecting column type for fields in Table.Meta.fields (fixes 498)
• Renamed Table.Meta.template to template_name (with deprecation warning for the former) 542 (fixes 520)
• Added Czech translation 533 by OndraRehounek
• Added table_factory 532 by ZuluPro

1.17.1

• Fix typo in setup.py for extras_require.

1.17.0

• Dropped support for Django 1.8, 1.9 and 1.10.
• Add extra_context argument to TemplateColumn 509 by ad-m
• Remove unnecessary cast of record to str 514, fixes 511
• Use django.test.TestCase for all tests, and remove dependency on pytest and reorganized some tests 515
• Remove traces of django-haystack tests from the tests, there were no actual tests.

1.16.0

This is the last version supporting Django 1.8, 1.9 and 1.10. Django 1.8 is only supported until april 2018, so consider upgrading to Django 1.11!

• Added tf dictionary to Column.attrs with default values for the footer, so footers now have class attribute by default 501 by mpasternak

1.15.0

• Added as=varname keyword argument to the {% querystring %} template tag,
  fixes 481
• Updated the tutorial to reflect current state of Django a bit better.
• Used OrderedDict rather than dict as the parent for utils.AttributeDict to make the rendered html more consistant accross python versions.
• Allow reading column attrs from a column's attribute, allowing easier reuse of custom column attributes (fixes 241)
• value and record are optionally passed to the column attrs callables for data rows. 503, fixes 500

1.14.2

• Added a row_counter variable to the template context in TemplateColumn (fixes 448)

1.14.1

• Do not fail if orderable=False is passed to ManyToManyColumn()

1.14.0

• Added separator argument to ManyToManyColumn.
• Allow mark_safe()'d strings from ManyToManyColumn.tranform()
• Disabled ordering on ManyToManyColumns by default.

1.13.0

• Made positional data argument to the table __init__() a keyword argument to make inheritance easier. Will raise a TypeError if ommitted.

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

Happy merging! 🤖

[pyup-bot]

Closing this in favor of #139