Release Notes: 0.7.0 beta.2

What's new since 0.7.0-beta.1?

• Based on git 2.46.2.
• Avoid showing an update notification for the current beta version when it is the latest release.
• Fixed git push --dry-run to not report spurious errors.
• Allow git push --dry-run to create metadata for the changesets the push would create.
• Various changes to download.py and git cinnabar self-update.