docs: add benchmarks page

[vplasencia]

Description

This PR:

• Adds the benchmarks page to the Semaphore documentation.

• Updates the docusaurus version because there was a warning in the console that was solved by using the latest docusaurus version.

Warning before updating the docusaurus version:

LoadableComponent uses the legacy contextTypes API which is no longer supported and will be removed in the next major release. Use React.createContext() with static contextType instead.

Related Issue(s)

Closes #815

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have run yarn format and yarn lint without getting any errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[cedoor]

Thank you vm @vplasencia! LGTM :)