2.0.0-beta.13 (2021-12-10)

Release to fix a bad npm publish in beta.12 and mitigate today's npm issues (https://status.npmjs.org/incidents/n4s34mwsdsp2)

Same code as beta.11, please refer to beta.11 changelog and release: https://github.com/facebook/docusaurus/releases/tag/v2.0.0-beta.11