Fixed compatibility issue in clicker (#19)

* Fixed compatibility issue in clicker

_clicker used python syntax that is only compatible with python 3.10+.
I changed the syntax to be compatible with earlier versions.
My research group uses this epon source library with python 3.9.6 and
are glad to contribute.
Package now requires the typing module as a dependency.

Committer Contact info:

H. Ryott Glayzer
email: code@ryott.gay

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* replaced old syntax with __future__

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update setup.cfg

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Co-authored-by: H. Ryott Glayzer <code@ryott.gay>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Ian Hunt-Isaak <ianhuntisaak@gmail.com>

mpl_point_clicker/_clicker.py

@@ -2,6 +2,7 @@
 
 # Copyright (c) Ian Hunt-Isaak.
 # Distributed under the terms of the Modified BSD License.
+from __future__ import annotations
 
 __all__ = [
     "clicker",