Install: open the release note after gopls upgrade finishes

[hyangah]

Maybe with webview

cc @stamblerre

[stamblerre]

Just tried working on this, but I don't think it's going to be possible if we're using GitHub for release notes.
I couldn't see the link in the iframe because of this error: [Embedded Page] Refused to frame 'https://github.com/' because an ancestor violates the following Content Security Policy directive: "frame-ancestors 'none'".

Based on https://stackoverflow.com/questions/38535491/trying-to-render-iframe-ancestor-violates-the-following-content-security-policy, this isn't something we can control. (I may not have fully understood this, but I think it's basically GitHub saying we can't put the link in an iframe?)