Update fleece for CBL-8494

[pasin]

No description provided.

[github-actions]

This is a release branch and commits are restricted.

Please confirm this PR is one of the following:

• A response to a customer ask
• A change per our security policy
• A non-functional change (e.g. changes needed for building an older version)
• A bug fix for a x.y.0 release
• A change that has been granted an exception (please comment)

[cbl-bot]

Code Coverage Results:

Type	Percentage
branches	64.5
functions	77.39
instantiations	71.03
lines	75.91
regions	72.18