x/website: incorrect expected release date for Go 1.18

[golangninja]

The expected release date was February, 2022; however, the date has already been exceeded. Please update the following page: https://tip.golang.org/doc/go1.18

[ianlancetaylor]

Thanks, my understanding is that that note will be removed as part of the release process.

CC @golang/release

[dmitshur]

The draft notice is indeed removed as part of resolving #47694.

I've sent CL 390374 to update the expected release date now,
and another CL that removes the notice for the release day.

[gopherbot]

Change https://go.dev/cl/390374 mentions this issue: _content/doc/go1.18: update expected release date