CHANGELOG.md: adjust the release date for 0.8

Because now it is past midnight. Also the year for 0.7 was wrong.
4 jobs for 0.8 in 4 minutes and 36 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Build
passed #358653
alpine

00:00:40

passed #358651
arch

00:04:32

passed #358652
debian

00:03:56

passed #358650
fedora

00:04:36

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