[wpiutil] circular_buffer: Use value initialization instead of passing zero (#3303)

This enables use of types that have a no-args constructor rather than one that takes an explicit zero value.
For numeric types, value initialization will result in a zero value, so this is not a functional change.

wpiutil/src/main/native/include/wpi/circular_buffer.inc

@@ -11,7 +11,7 @@
 namespace wpi {
 
 template <class T>
-circular_buffer<T>::circular_buffer(size_t size) : m_data(size, T{0}) {}
+circular_buffer<T>::circular_buffer(size_t size) : m_data(size, T{}) {}
 
 /**
  * Returns number of elements in buffer