Bump version for beta

Update changelog.json

Co-Authored-By: iAmWillShepherd <iAmWillShepherd@users.noreply.github.com>

When in doubt, ask Billy

Co-Authored-By: niik <j.markus.olsson@gmail.com>

bump version and add changelog

first pass at release notes

more edits

bump version for first beta of 1.5.2

Merge pull request desktop#6455 from desktop/i-told-you-i-didnt-have-…

…conflicts

Backport work from PR desktop#6452

Update changelog.json

1.5.1-beta5