doc: update post sec release process

doc: update post sec release process · nodejs/node@3c082d4

Original file line number	Diff line number	Diff line change
`@@ -156,14 +156,10 @@ security announcements for more information.`
`156`	`156`
`157`	`157`	`## Post-Release`
`158`	`158`
`159`		`-* [ ] 1\. Merge the Next Security Release PR:`
`160`		-* This involves moving the `vulnerabilities.json` file from
`161`		-`security-release/next-security-release` to the `security-release/YYYY-MM-DD`
`162`		`- folder and merging the PR.`
`163`		`-`
`164`		`-* [ ] 2\. Cleanup:`
	`159`	`+* [ ] 1\. Cleanup:`
`165`	`160`	* [ ] `git node security --cleanup`. This command will:
`166`		`-* Close PRs and backports.`
	`161`	`+* Update next-security-release folder`
	`162`	+* Close all PRs and backports labeled with `Security Release`.
`167`	`163`	`* Close HackerOne reports:`
`168`	`164`	`* Close Resolved`
`169`	`165`	`* Request Disclosure`