sig-scheduling: update descheduler meeting times

[jackfrancis]

This PR updates the community docs about changes to the biweekly descheduler meeting schedule.

Which issue(s) this PR fixes:

Fixes #

[jackfrancis]

/assign @Huang-Wei @ahg-g @alculquicondor

[Huang-Wei]

/lgtm /approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Huang-Wei, jackfrancis, pacoxu

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