Update tablib to 0.14.0

[pyup-bot]

This PR updates tablib from 0.13.0 to 0.14.0.

Changelog

0.14.0

Deprecations

- The 0.14.x series will be the last to support Python 2

Breaking changes

- Dropped Python 3.4 support

Improvements

- Added Python 3.7 and 3.8 support
- The project is now maintained by the Jazzband team, https://jazzband.co
- Improved format autodetection and added autodetection for the odf format.
- Added search to all documentation pages
- Open xlsx workbooks in read-only mode (316)
- Unpin requirements
- Only install backports.csv on Python 2

Bugfixes

- Fixed `DataBook().load` parameter ordering (first stream, then format).
- Fixed a regression for xlsx exports where non-string values were forced to
strings (314)
- Fixed xlsx format detection (which was often detected as `xls` format)

Links

• PyPI: https://pypi.org/project/tablib
• Changelog: https://pyup.io/changelogs/tablib/
• Docs: https://tablib.readthedocs.io