Improve update method from Terran, Protoss and Zerg state classes

[RickFqt]

We need to find a way to add custom modifications on the values stored in units_amount_info on these classes. This might be done in two possible ways:

• Create another class that overrides the update method.
• Develop a mechanism that allows you to change only the value of units_amount_info.

[alvarofpp]

After creating this mechanism, you need to create a class for Terran with the values removed in this commit: ca80acf