updated README

README.md

@@ -1,2 +1,13 @@
 # setup-pipenv
-A GitHub action to setup and activate a virtual environment with pipenv
+
+A GitHub action to install python and setup + activate a virtual environment with pipenv.
+Other than existing pipenv GitHub actions, the virtual environment is activated after it is set up.
+So the rest of the workflow doesn't need to know that pipenv was used in creating the environment.
+
+## Inputs
+
+- `python-version`: The Python version to use (e.g., `3.9`)
+- `additional-dependencies`: (optional) A list of python libraries to be installed via pip
+after setting up the virtual environment with the dependencies from `Pipfile.lock`.
+This might be useful if there are certain dependencies only for the workflow
+that are not needed for the rest of the project.