DEV: add requirements-tests.txt on make install target (#791)

* DEV: adds 'pip install -r requirements-tests.txt' recipe to 'make install' target on Makefile

Co-authored-by: Gui-FernandesBR <[email protected]>

Author: leogrosa

Makefile

@@ -21,6 +21,7 @@ install:
 	$(PYTHON) -m pip install --upgrade pip
 	pip install -r requirements.txt
 	pip install -r requirements-optional.txt
+	pip install -r requirements-tests.txt
 	pip install -e .
 
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