Added simple cocotb testbench for CU #38

	name: Cocotb Test

	on:
	push:
	branches:
	- master
	paths:
	- 'testbench/cocotb/**'
	- 'rtl/**'
	pull_request:
	branches:
	- master
	paths:
	- 'testbench/cocotb/**'
	- 'rtl/**'

	jobs:
	test:
	runs-on: ubuntu-latest

	steps:
	- name: Checkout code
	uses: actions/checkout@v2

	- name: Setup Python
	uses: actions/setup-python@v2
	with:
	python-version: '3.8'

	- name: Install Dependencies
	run: \|
	sudo apt-get update -q
	sudo apt-get install -y iverilog
	pip install cocotb

	- name: Run Cocotb Test
	working-directory: testbench/cocotb # Subsequent step will back to root directory automatically
	run:
	make -f Makefile all

	- name: Clean up
	working-directory: testbench/cocotb
	run:
	make -f Makefile cleanup

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