chore: add project script

Added the script 'jcloud-docsgen' to pyproject.toml so that jCloud Docsgen can
be run directly without using 'python3 -m ...'.

pyproject.toml

@@ -10,6 +10,9 @@ dependencies = ["docstring-parser"]
 requires-python = ">=3.10"
 license = "Apache-2.0"
 
+[project.scripts]
+jcloud-docsgen = "jcloud_docsgen.cli.cli:main"
+
 [tool.poetry]
 packages = [
     { include = "jcloud_docsgen", from = "src"}