message: Use 0.0 rather than 0 to make sure the InstructionParameter variant of U3 gate is of double type
  In some parts of XACC, downstream code might just assume the U3 params are of double type and try to cast them.
diff: @@ -77,7 +77,7 @@ void _apply_cu(std::shared_ptr<CompositeInstruction> circuit, double theta,
  circuit->addInstruction(
  provider->createInstruction("U", {target},
  std::vector<xacc::InstructionParameter>{
  - -theta / 2, 0, -(lam + phi) / 2.}));
  + -theta / 2, 0.0, -(lam + phi) / 2.}));
  circuit->addInstruction(
  provider->createInstruction("CNOT", {control, target}));
  