Qiskit-ionq

This release allows selection of a gateset parameter when creating an IonQBackend via provider.get_backend.

qis behaves identically to the previous release of the qiskit_ionq package, allowing a standard set of Quantum Information Science gates (rx, ry, etc) and supporting transpilation to these gates.
native requires the use only of the new gates qiskit_ionq.GPIGate, qiskit_ionq.GPI2Gate, qiskit_ionq.MSGate, and does not yet support transpilation.
This allows qiskit-ionq users to program IonQ QPUs at the hardware level.

This release allows selection of a `lang` parameter when creating an IonQBackend via `provider.get_backend`.

* `qis` behaves identically to the previous release of the qiskit_ionq package, allowing a standard set of Quantum Information Science gates (rx, ry, etc) and supporting transpilation to these gates.
* `native` requires the use only of the new gates `qiskit_ionq.GPIGate`, `qiskit_ionq.GPI2Gate`, `qiskit_ionq.MSGate`, and does not yet support transpilation.

This allows qiskit-ionq users to program IonQ QPUs at the hardware level.

* Fixes functionality added in 0.2.0. When a more specific target is specified as for ex: `ionq_qpu.harmony` this is now sent through to the IonQ service.

A pre-release version for testing:
* Increase qubit cap to 23.

This release includes:

Addition of support for new IonQ backends (ionq_qpu.harmony, ionq_qpu.aria.1)
Removal of support for python3.6

This release includes:
* Addition of support for new IonQ backends (ionq_qpu.harmony, ionq_qpu.aria.1)
* Removal of support for python3.6