message: governance: fix small typo
diff: * Start doing PRs and code reviews under the guidance of your senior maintainer.
  * After a period of 1-2 months the existing senior maintainers will discuss granting "standard"
  maintainer access.
  -* "Standard" maintainer access can be upgraded to "senior" maintainer access aft
  +* "Standard" maintainer access can be upgraded to "senior" maintainer access after another 1-2
  + months of work and another conference of the existing senior committers.
  ## Maintainer responsibilities
  * Monitor email aliases.
  * Monitor Slack (delayed response is perfectly acceptable).
  * Triage GitHub issues and perform pull request reviews for other maintainers and the community.
  -* In general continue to be willing to spend at least 25% of ones time working on Envoy (~1.25
  +* In general continue to be willing to spend at least 25% of one's time working on Envoy (~1.25
  business days per week).
  * Note that currently the above is performed by all maintainers in a best-effort/haphazard way. In
  the future we may decide to move to an "on-call" rotation.
  