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

Author: leogrosa

CHANGELOG.md

@@ -39,6 +39,7 @@ Attention: The newest changes should be on top -->
 
 - DOCS: reshape docs (closes #659) [#781](https://github.com/RocketPy-Team/RocketPy/pull/781)
 - MNT: EmptyMotor class inherits from Motor(ABC) [#779](https://github.com/RocketPy-Team/RocketPy/pull/779)
+- DEV: add requirements-tests.txt on make install target [#790](https://github.com/RocketPy-Team/RocketPy/issues/790)
 
 ### Fixed
 

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 .
 
 format: