Patch: correct docs

Correct some errors in docs

Add flags input

Previously, file paths could not be specified by the user of this action. That is now implemented with this functionality

Add report file path

This update lets users specify a path to the coverage report file

with:
  file: ./coverage.xml

Linting, spelling fixes

Just a few quick spelling fixes across a couple files

Patch public repo uploads

Bug fix: Public repositories should be able to upload without a token. Prior to this patch, a token would've been required to upload for all public repos using the Codecov action

Initial release

Capabilities:

• Invoke Codecov's bash uploader
• Use token to validate upload