First-draft release notes for 18.2 are done

Draft back-branch release notes are up at

https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=c6881f792281d1abeba9acf3fe7972da091f2bbd

(There are one or two items that don't actually apply to v18,
only older branches. I'll remove those after cloning this text
into the older branches.)

Please send comments and corrections by Sunday.

regards, tom lane