Use paginate method for pr comments

This allows `pull_requests_comments` to work with auto pagination.
Merge pull request #526 from gylaz/paginate-comments

Use paginate method for pr comments
v3.5.2
Release 3.5.2
[ci skip] Add example for create a pull request.
Deployment auto_merge defaults to true

See https://developer.github.com/v3/repos/deployments/#create-a-deployment
Remove `force` option from create_deployment docs

According to the docs, there is no such option:

https://developer.github.com/v3/repos/deployments/#create-a-deployment
auto_merge is a boolean, not string
document the task option
document the environment option
Fix pubsubhubbub spec

Updated webmock doesn't assume the parameter passed to Stub is body by default anymore.
Merge pull request #529 from octokit/fix-failing-pubsub-spec

Fix pubsubhubbub spec
Merge pull request #528 from bgentry/deployment-doc-fixes

Deployment doc fixes
Document required_contexts option for Octokit::Client#create_deployment
Fix typo in update issue docs
Merge pull request #530 from codetree/fix-issue-doc-type

Fix typo in update issue docs
Overload the #update_issue method to allow partial updates

The old argument structure still works as usual:

    update_issue(repo, number, title, body, options)

But now, you have the option of passing the title and body
attributes in the options hash (or omitting these attributes
if they should not be changed):

    update_issue(repo, number, options)
Merge pull request #531 from codetree/allow-partial-issue-updates

Overload the #update_issue method to allow partial updates
Fix link to pessimistic versioning explanation in README

Fixes #532
[skip ci]
Merge pull request #527 from JuanitoFatas/doc/create-pr-example

[ci skip] Add example for create a pull request.