[WIP] Heroku Dyno

[Arique1104]

Description

Updates ReadMe for Heroku costs updates. I believe this pull request needs to be verified through some outreach to the community.

Is the community able to start a fresh new Heroku Spoke Instance and upload a list through the NPGVAN API a contact list of 80K with a $25 dyno without the application crashing?

If we can gather more responses from the community about their experience with the API VAN linkage, then we can comfortably close or merge this pull request.

Checklist:

• [x] I have manually tested my changes on desktop and mobile
• [x] The test suite passes locally with my changes
• [x] My change is 300 lines of code or less, or has a documented reason in the description why it’s longer
• [x] I have made any necessary changes to the documentation
• [x] My PR is labeled [WIP] if it is in progress