Katsdptelstate

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* Improvements to internal type hints (133)
* Get lupa version (for testing) from katsdpdockerbase (134)
* Fix variables referenced before use in exception path (135)
* Improve error message when opening old files containing pickles (136)

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* Upgrade to redis-py>=4.2 and fakeredis>=2, fix test warnings (132)
* This now requires at least Python 3.7 and no more aioredis

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* Switch to aioredis 2.x (124)
* Add async (and synchronous) `RedisBackend.from_url` constructor (125, 126)
* Switch from nose to pytest (129)
* Remove `Endpoint.multicast_subscribe` and `netifaces` dependency (130)
* Fix Lua script for `set_indexed` so that `wait_indexed` actually works (127)
* Make aio `wait_key` more robust (128)
* General cleanup (122, 123)

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* Add asynchronous RDBWriter class (108)
* Use a transaction for get_range instead of Lua: faster on server side (110)
* Multiplex aio pubsubs over pool's standard connection (113)
* Require hiredis for speed and aioredis<2 for compatibility (114, 118)
* Improve `wait_keys` responsiveness for `MemoryBackend` (111, 116)
* Avoid blocking the Redis server on telstate.clear (112)
* Update Docker image to use Redis 6.x instead of 4.x (109)
* Support older HMSET Redis command in unit tests (107)
* Requirements cleanup (115, 117, 119, 120)

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* Remove Python 2 support. At least Python 3.5 is required.
* Remove support for old versions of redis-py (100)
* Use redis-py health checks to improve robustness (99)
* Add "indexed" keys (98)
* Add an asyncio interface (103)
* No longer throw InvalidKeyError when setting a key that shadows a method (102)
* Add type annotations for mypy (101)

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* Deprecate Python 2 support: this is the last release that will support Python 2 (94)
* Remove ``get_message`` and ``send_message``, which were never used (89)
* Publish the documentation on https://katsdptelstate.readthedocs.io (#90)
* Disable pickles by default for security (92)