Review docs for createSite endpoint - repo id type

[codebyuma]

A customer in the forums mentioned that they were trying to use the createSite endpoint to connect to a Bitbucket repo. They were confused as the open-api docs say the repo id (in the repoInfo object) should be an integer but they could only find a string value from Bitbucket.

The string value worked correctly for the user and Fool was able to confirm that both integer and string are accepted on Slack.

This issue is to review whether we might be able to update the docs to include both types (and update the docs, if possible). Also relates to #131.

[codebyuma]

Also related to #130