Fix API doc link in README.md

[DenisKorkut-bcgov]

Description

The link to the API documentation was pointing to a defunct route/endpoint.

Corrected the readme link to point to the current endpoint.

Types of changes

Documentation (non-breaking change with enhancements to documentation)

Checklist

• I have read the CONTRIBUTING doc
• I have checked that unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have updated the OpenAPI 3.0 v*.api-spec.yaml documentation (if appropriate)
• I have added necessary documentation (if appropriate)

Further comments

Assuming a partial checklist okay here, as it is only an edit to a readme.