[Snyk] Upgrade @octokit/rest from 18.5.6 to 18.6.4

Snyk has created this PR to upgrade @octokit/rest from 18.5.6 to 18.6.4.

merge advice :information_source: Keep your dependencies up-to-date. This makes it easier to fix existing vulnerabilities and to more quickly identify and fix newly disclosed vulnerabilities when they affect your project.

The recommended version is 5 versions ahead of your current version.
The recommended version was released 21 days ago, on 2021-06-29.

Release notes

Package name: @octokit/rest

18.6.4 - 2021-06-29
18.6.4 (2021-06-29)

Bug Fixes
- typescript: .security_and_analysis.secret_scanning property in repository responses (#77) (36373fe)
18.6.3 - 2021-06-26
18.6.3 (2021-06-26)

Bug Fixes
- deps: update dependency @ octokit/plugin-rest-endpoint-methods to v5.3.4 (4d82495)
18.6.2 - 2021-06-24
18.6.2 (2021-06-24)

Bug Fixes
- typescript: pagination parameters for .search.topics() and .search.labels() via @ octokit/plugin-rest-endpoint-methods v5.3.3 (#72) (acc61e3)
18.6.1 - 2021-06-23
18.6.1 (2021-06-23)

Bug Fixes
- typescript: many type improvements via @ octokit/plugin-rest-endpoint-methods v5.3.2 (#71) (127e0a8)
18.6.0 - 2021-06-12
18.6.0 (2021-06-12)

Features
- set error.response (#64) (59cf96f)
18.5.6 - 2021-06-01
18.5.6 (2021-06-01)

Bug Fixes
- release to resolve problem with skypack (#57) (135b44b)