Make the calculators final

Author: Vectorial1024

src/CodeCalculator/CodeCalculatorFloat.php

@@ -9,7 +9,7 @@
  * A Open Location Code calculator that uses float.
  * As such, this is usable on any PHP version. but may have unforeseen inaccuracy.
  */
-class CodeCalculatorFloat extends AbstractCodeCalculator
+final class CodeCalculatorFloat extends AbstractCodeCalculator
 {
     // Value of the most significant latitude digit after it has been converted to an integer.
     // Note: to ensure 32bit PHP compatibility, this is now a precisely-represented float.

src/CodeCalculator/CodeCalculatorInt.php

@@ -10,7 +10,7 @@
  * A Open Location Code calculator that uses "long" int.
  * As such, this has ensured accuracy, but cannot be used in 32-bit PHP.
  */
-class CodeCalculatorInt extends AbstractCodeCalculator
+final class CodeCalculatorInt extends AbstractCodeCalculator
 {
     // Value of the most significant latitude digit after it has been converted to an integer.
     // Note: since we are using 64-bit PHP, this can be an int.