Hotfix: delete numpy.str in datapacking

Update requirements

Update GHA to use Ubuntu 20.04

Pure C++ Verilator-based FIFO sizing

[Tests] Fix ipstitch test for VitisBuild

Hotfix/end2end tests

[pre-commit] Update flake8 link

Minor fix to attribute naming

- move input token counting to after clock tick
- introduce separate tracker for last seen output
- introduce (disabled by default) vcd tracing capabilities

[Fix] VitisBuild