py-cachelib: updated to 0.5.0

Version 0.5.0
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-  Cache types now have configurable serializers.

Version 0.4.1
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-  Fix break in ``RedisCache`` when a host object was passed
    in ``RedisCache.host`` instead of a string.

Version 0.4.0
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-  All cache types now implement ``BaseCache`` interface both
    in behavior and method return types. Thus, code written
    for one cache type should work with any other cache type.
-  Add type information for static typing tools.
-  ``FileNotFound`` exceptions will not be logged anymore
    in ``FileSystemCache`` methods in order to avoid polluting
    application log files.

(adam)