v0.28

Silences are now deduplicated (moved to the footer) in the UI when entire alert group was silenced by a single silence.

Full changelog:

• #506 feat(ui): deduplicate silences
• #505 feat(ui): truncate silences with long comments
• #503 fix(backend): fix the syntax of tools.go
• #498 chore(ui): upgrade all 3rd party dependencies