adding subproject back in as https #297

	name: Unit Tests

	on: [push]

	jobs:
	build:

	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v2
	- name: clone
	run: git submodule update --init --recursive
	- name: apt install
	run: sudo apt-get install -y build-essential cmake libgtest-dev libeigen3-dev
	- name: install gtest
	run: \|
	cd /usr/src/gtest
	sudo cmake CMakeLists.txt
	sudo make
	sudo cp ./lib/libgtest*.a /usr/lib
	- name: cmake
	run: \|
	mkdir build
	cd build
	cmake .. -DBOARD_TO_BUILD=test -DCMAKE_BUILD_TYPE=Release
	- name: make
	run: \|
	cd build
	make
	- name: test
	run: \|
	cd build
	./test/unit_tests

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