Update comments in RequestContext class to point to base url of requests library documentation instead of /latest.  Also, add a note informing user that they should match up the doc version with the version of requests the SDK is currently using.
Update comments in RequestContext class to point to base url of requests library documentation instead of /latest.  Also, add a note informing user that they should match up the doc version with the version of requests the SDK is currently using.

penzance/canvas_python_sdk