Bump @octokit/rest from 18.12.0 to 19.0.3

Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 18.12.0 to 19.0.3.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v18.12.0...v19.0.3)

---
updated-dependencies:
- dependency-name: "@octokit/rest"
  dependency-type: direct:development
  update-type: version-update:semver-major
...
Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -12,7 +12,7 @@
     "@babel/preset-react": "^7.0.0",
     "@hypothesis/frontend-build": "1.2.0",
     "@hypothesis/frontend-shared": "5.0.0",
-    "@octokit/rest": "^18.0.0",
+    "@octokit/rest": "^19.0.3",
     "@rollup/plugin-babel": "^5.3.0",
     "@rollup/plugin-commonjs": "^22.0.0",
     "@rollup/plugin-json": "^4.1.0",