Create the cyclomatic complexity graphs for each class used for the unit tests

Update the README in order to inform about the objective of the project, the concepts applied, the results generated and how to use the repository

• Build a class with the state of the federation (2 characters) and the value of a product as attributes.
• Build the respective get/set methods.
• The setState method should criticize the states of the federation and the Federal District.
• The setValue method must not allow a value less than or equal to zero.
• Build a float method calculateTax(), which should apply the state's aliquot to the value of the product, as shown at the end of the statement.
• Build all the tests, both for valid situations (all states) and invalid situations (exceptions).
• Use the BeforeEach method to start the object.