docs: use importlib.metadata instead of pkg_resources to fix Sphinx RTD build

Author: PrasannaPal21

docs/conf.py

@@ -12,10 +12,10 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-from pkg_resources import get_distribution
+from importlib.metadata import version as get_version
 
 
-release = get_distribution("glidertools").version
+release = get_version("glidertools")
 version = ".".join(release.split(".")[:2])
 
 # If extensions (or modules to document with autodoc) are in another directory,