* Split kill_house() fix issues #1234

Details View issues #1234

* Removing the catch finally

* rename wait_horse() to wait_for_horse()

* rename wait_horse() to wait_for_horse()

* update test_handle_shutdown_request()

Change test_handle_shutdown_request() exitcode assert

* Restore kill_horse() output

* optimization wait_for_horse()

* Fix scheduler on Python 3.8

* Use Python 3.8.3 for test

The variable contains the server version and allows to determine
available features. This is relevant for API changes like HSET mappings
in version 4.0.0 or LPOS in version 6.0.6.

To keep the number of connection.info() calls low, the information is
*cached* once determined, as a server version unlikely changes while
keeping the connection up.

Signed-off-by: Paul Spooren <mail@aparcar.org>

With revision 02eb983e90aeb8e878e5c0f9989b7b701b8ad21a the `python_requires` was set to `3.4`

Only test on major versions to reduce number of tests.

Signed-off-by: Paul Spooren <mail@aparcar.org>

* CI: replace travis with GitHub action matrix

The GitHub action runs the same tests as travis however using a more
complex matrix:

Python versions: 3.5, 3.6, 3.7, 3.8
Python 3.4 is dropped by redis-py, therefore not required in the tests.

Redis versions: 3, 4, 5, 6
The different Redis versions offer different features and this allows
checks for compatibility.

redis-py versions: 3.5.0, 3.5.3
3.5.0 is the oldest supported version, 3.5.3 is the latest upstream
verison

Signed-off-by: Paul Spooren <mail@aparcar.org>

* CI: Add flake8 lint action

This actions runs `flake8` and shows style problems of the code. It uses
th GitHub default options which handle most problems as warnings. These
rules could become slowly more strict.

Signed-off-by: Paul Spooren <mail@aparcar.org>

As `redis-py` in version 3.5.0 is now required, whoch only support
Python 3.5+, we should remove Python 3.4 from the supported Python
versions as well.

Signed-off-by: Paul Spooren <mail@aparcar.org>