Edit v1.0.0-alpha.4 changelog

Author: mxmason

CHANGELOG.md

@@ -9,8 +9,9 @@ Prior to v1.0.0-alpha.1, logs were generated by [`auto-changelog`](https://githu
 
 ## [v1.0.0-alpha.4](https://github.com/netlify-labs/netlify-plugin-a11y/compare/v1.0.0-alpha.3...v1.0.0-alpha.4)
 ### Changed
-- Eliminated some redundancy when defining `directoryFilter` internally.
 - Added a pre-release notice to the README, as well as other copy cleanup.
+- Internal: Made the plugin much more performant and memory-efficient by keeping Puppeteer alive through the run and writing our own reporter.
+- Internal: some redundancy when defining `directoryFilter`.
 
 ## [v1.0.0-alpha.3](https://github.com/netlify-labs/netlify-plugin-a11y/compare/v1.0.0-alpha.2...v1.0.0-alpha.3)
 ### Changed