feat: create release command

[pd93]

Hey @andreynering, I was messing around with the changelog yesterday and I came up with a way that we can automate the release process a bit more. I'm curious on your thoughts as this would mostly effect you.

• New command in ./cmd/release
• Can be run with task release -- major|minor|patch|x.x.x
• Automatically set the version/date in the both changelogs
• Automatically convert github autolinks (#issue/@user) to FQDNs in the website changelog
  • This means we can keep the short autolinks in the main CHANGELOG.md which is a bit easier to write/manage

I've also reformatted both copies of the changelog slightly.

• 80 character limit
• Removed the hard-to-write FQDNs from CHANGELOG.md as they now get converted

Its worth noting that PRs will be linked with /issues in the URL as there is no way to differentiate between issues/PRs using autolinks. However, as PRs are just a special type of issue in GitHub, the link will still work - it just redirects.

[andreynering]

Looks good. Thanks!