v2.6.4

Changelog

• cff82cd Solutions for kosli-dev/server#881 and kosli-dev/server#885
• 3658efe Tweak grammar of text in docs.kosli.com/content/getting_started/evidence.md, eg add 'the' [ci skip]
• d1694f5 Docs: update custom webhooks payload
• d7bf0cb Merge branch 'improve-docs'
• e6e708e Elaborate on commit/artifact evidence
• 127a6e7 fixes in evidence vault section
• bae0c1b fixes in evidence vault section
• 36deb79 fixes in evidence vault section
• a48c1ab Docs: fix relative links
• f5ca22a Docs: add docs for webhooks notifications
• 31d437f Update evidence docs
• 8e39f82 elaborate on evidence flags