Merge pull request home-assistant#3231 from robmarkcole/patch-1

State that dependencies are from pypi

source/developers/development_checklist.markdown

@@ -12,7 +12,7 @@ footer: true
 
 Before you commit any changes, check your work against these requirements:
 
-- All dependencies are included via the `REQUIREMENTS` variable in your platform or component and only imported inside functions that use them
+- All dependencies from [pypi](https://pypi.python.org/pypi) are included via the `REQUIREMENTS` variable in your platform or component and only imported inside functions that use them
 - New dependencies are added to `requirements_all.txt` (if applicable), using `script/gen_requirements_all.py`
 - The `.coveragerc` file is updated to exclude your platform if there are no tests available or your new code uses a third-party library for communication with the device, service, or sensor
 - Documentation is developed for [home-assistant.io](https://home-assistant.io/)