Replace limit=0 query parameter to avoid 400 Bad Request responses

[mat-mil]

Issue being resolved: #301

Solution description

How are we solving the problem?
__get_all_entities() method needs more work than this easy fix.

1. The API of TestRail 8.0.6 response.response_text["_links"]["next"] and the link inside does not contain ? marking the start of query parameters so it is not easy to parse with built-in libraries (e.g. urllib.parse.urlparse())
2. One of the requests mentioned in __get_all_sections() method sets query parameter limit to 0 and fails with 400 Bad Request response #301 has query-param-like entity appended and set to 0, which causes the server to respond with 400 Bad Request.
   Pay attention to this URL
   url: https://<redacted>/api/v2/get_sections/<project_id>&suite_id=<suite_id>&limit=0&offset=0
   There is no ? so technically (based on urllib.parse.urlparse) there are no query parameters at all.
3. Having this in mind, we only check whether the limit=0 string exists in response.response_text["_links"]["next"] and if that's true, we replace it with limit=250

Changes

Explained above

Potential impacts

Don't see. Ideally it should not be a hardcoded value. Maybe it should be investigated further why TestRail API returns such link in response.response_text["_links"]["next"] bodies.

Steps to test

Follow reproduction steps from #301

PR Tasks

• PR reference added to issue
• README updated
• Unit tests added/updated