Improve error message when deploying to invalid endpoint

[marktani]

Feature Request

What feature are you missing?

When deploying to an invalid endpoint, you'll get this response currently (prisma@1.9-beta):

For example, enter endpoint: localhost:4466/test/dev instead of endpoint: http://localhost:4466/test/dev in prisma.yml when running prisma.deploy.

The error message could say:

Invalid endpoint in prisma.yml: localhost:4466/test/dev!