Fix Sphinx configuration with Python 3.12

Python 3.12 has removed 'pkg_resources' from the standard library:
https://docs.python.org/3/whatsnew/3.12.html.

docs/conf.py

@@ -16,7 +16,7 @@
 
 # pylint: skip-file
 
-from pkg_resources import get_distribution
+from faker_wifi_essid import __version__ as VERSION
 
 
 # -- Project information -----------------------------------------------------
@@ -26,7 +26,7 @@
 author = 'Paul-Emmanuel Raoul'
 
 # The full version, including alpha/beta/rc tags
-release = get_distribution("faker_wifi_essid").version
+release = VERSION
 
 
 # -- General configuration ---------------------------------------------------