Update README.md file according to "README.md template"

1. Bulleted lists denoted by dashes (-) , however * is used in patch.

@Charchil Khandelwal, @Nupur Badola thx, but I would like to remind you about https://www.drupal.org/drupalorg/docs/marketplace/abuse-of-the-contribut... → especially the part:

Those abusive behaviors include:
Bulk posting of low-effort issues, such as:
Conversion from README.txt to README.md or other minor readme fixes

It is great that you want to help, but please invest your time in actual help and not 'low-effort issues' as this one. If you want to help this project, the project page is listing next major things that needs to be done for first stable release like:

- Implement all tracker configuration options https://umami.is/docs/tracker-config
- Cron implementation of local js cache
- Tests
- Support custom tracker events