update release tool to reflect 72 hour release cut in RFC 695

Created by: coury-clark

Updating the release tool to reflect the new release cut. This is a trivial PR that only changes the field name for future readers, and updates documentation.

Test plan

Dry run of yarn run release tracking:timeline to ensure the fields are still appropriately assigned to the calendar API requests.

➜  sourcegraph git:(main) ✗ yarn run release tracking:timeline
yarn run v1.22.17
$ cd dev/release && yarn run release tracking:timeline
$ ts-node --transpile-only ./src/main.ts tracking:timeline
Using versions: { upcoming: 3.41.0, previous: 3.40.2 }
dryRun.calendar=true, skipping calendar event creation [
  {
    title: 'Security Team to Review Release Container Image Scans 3.41',
    description: '(This is not an actual event to attend, just a calendar marker.)',
    anyoneCanAddSelf: true,
    attendees: [ '[email protected]' ],
    transparency: 'transparent',
    startDateTime: '2022-06-13T18:00:00.000Z',
    endDateTime: '2022-06-13T18:01:00.000Z'
  },
  {
    title: 'Cut Sourcegraph 3.41',
    description: '(This is not an actual event to attend, just a calendar marker.)',
    anyoneCanAddSelf: true,
    attendees: [ '[email protected]' ],
    transparency: 'transparent',
    startDateTime: '2022-06-17T18:00:00.000Z',
    endDateTime: '2022-06-17T18:01:00.000Z'
  },
  {
    title: 'Release Sourcegraph 3.41',
    description: '(This is not an actual event to attend, just a calendar marker.)',
    anyoneCanAddSelf: true,
    attendees: [ '[email protected]' ],
    transparency: 'transparent',
    startDateTime: '2022-06-20T18:00:00.000Z',
    endDateTime: '2022-06-20T18:01:00.000Z'
  },
  {
    title: 'Deploy Sourcegraph 3.41 to managed instances',
    description: '(This is not an actual event to attend, just a calendar marker.)',
    anyoneCanAddSelf: true,
    attendees: [ '[email protected]' ],
    transparency: 'transparent',
    startDateTime: '2022-06-21T18:00:00.000Z',
    endDateTime: '2022-06-21T18:01:00.000Z'
  }
]
✨  Done in 4.16s.