Pystreamer

What's Changed
* Switch to github actions and use python 3.8+ by Arnoldosmium in https://github.com/Arnoldosmium/pystreamer/pull/9
* Configure deploy and remove travis by Arnoldosmium in https://github.com/Arnoldosmium/pystreamer/pull/10


**Full Changelog**: https://github.com/Arnoldosmium/pystreamer/compare/0.4.2...0.4.3

What's Changed
* Add advanced stream generators by Arnoldosmium in https://github.com/Arnoldosmium/pystreamer/pull/8


**Full Changelog**: https://github.com/Arnoldosmium/pystreamer/compare/0.4.0...0.4.2

[Impl break] `Zipper` operator flips the meaning of its boolean flag
[Feature] Add `constant_of` `iterate` `generate` stream generators
[Feature] Add set cartesian product family generators
[Feature] Add text buffer split family generators

[Fix] bugs of stream operators processing incorrectly on `None` elements
[Feature] `cross` operation
[Feature] adjacent element pair operation family
[Feature] `zip` family operations
[Feature] collapse family operations
[Feature] `has` family operation
[Feature] adjacent group operations
[Feature] group by operations

[Feature] add `sorted`, `peek`, `intersperse`, element-based filter functions, `reduce_right`
[Feature] add count / key options to distinct operation

[Break] Remove the support of `Dragon` as an alias of `Stream`
[Feature] Add collector definition and collector for counting
[Feature] Add commonly used stream consumer functions - now very similar to `Stream` of Java