Update flask_caching to 1.7.2

[pyup-bot]

This PR updates flask_caching from 1.4.0 to 1.7.2.

Changelog

1.7.2

**This is the last version supporting Python 2!**

- Do not run a cached/memoized function if the cached return value is None.
PR `108 <https://github.com/sh4nks/flask-caching/pull/108>`_.

1.7.1

- Fix introspecting Python 3 functions by using varkw.
PR `101 <https://github.com/sh4nks/flask-caching/pull/101>`_.
- Remove leftover files (``uwsgi.py``) in PyPI package. See issue
`102 <https://github.com/sh4nks/flask-caching/issues/102>`_ for more details.

1.7.0

- Added a feature called 'response_filter' which enables one to only
cache views depending on the response code.
PR `99 <https://github.com/sh4nks/flask-caching/pull/99>`_.
- A DeprecationWarning got turned into a TypeError.

1.6.0

- The ``delete_many`` function is now able to ignore any errors and continue
deleting the cache. However, in order to preserve backwards compatibility,
the default mode is to abort the deletion process. In order to use the new
deletion mode, one has to flip the config setting ``CACHE_IGNORE_ERRORS`` to
``True``. This was and still is only relevant for the **filesystem** and
**simple** cache backends.
PR `94 <https://github.com/sh4nks/flask-caching/pull/94>`_.
- Re-added the ``gaememcached`` CACHE_TYPE for improved backwards compatibility.
- Documentation improvements

1.5.0

- Add support for a Redis Sentinel Cluster.
PR `90 <https://github.com/sh4nks/flask-caching/pull/90>`_.
- Parameterize the hash function so alternatives can be used.
PR `77 <https://github.com/sh4nks/flask-caching/pull/77>`_.
- Include the deprecated ``werkzeug.contrib.cache`` module in Flask-Caching.
PR `75 <https://github.com/sh4nks/flask-caching/pull/75>`_.

Links

• PyPI: https://pypi.org/project/flask-caching
• Changelog: https://pyup.io/changelogs/flask-caching/
• Repo: https://github.com/sh4nks/flask-caching
• Docs: https://pythonhosted.org/Flask-Caching/