Merge pull request #311 from RocketPy-Team/readme-typo-fix

changes addTrapezoildalFins to addTrapezoidalFins

Author: GabrielBarberini

README.md

@@ -244,7 +244,7 @@ Calisto.setRailButtons([0.2, -0.5])
 
 NoseCone = Calisto.addNose(length=0.55829, kind="vonKarman", distanceToCM=0.71971)
 
-FinSet = Calisto.addTrapezoildalFins(4, span=0.100, rootChord=0.120, tipChord=0.040, distanceToCM=-1.04956)
+FinSet = Calisto.addTrapezoidalFins(4, span=0.100, rootChord=0.120, tipChord=0.040, distanceToCM=-1.04956)
 
 Tail = Calisto.addTail(topRadius=0.0635, bottomRadius=0.0435, length=0.060, distanceToCM=-1.194656)
 ```