all: swap satori's uuid package to gofrs

[mdanzinger]

This updates the sample bookshelf app to use the community recommended gofrs uuid package.

go.uuid is effectively unmaintained and contained at least one critical security flaw which took half a year to be merged as the owner isn't active. See satori/go.uuid#75

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[mdanzinger]

I signed it!

[googlebot]

CLAs look good, thanks!

[tbpg]

Thank you! Would you mind updating appengine/gophers/gophers-6/main.go and appengine_flexible/analytics/analytics.go, too?

[broady]

Thanks, great catch.

[mdanzinger]

Thank you! Would you mind updating appengine/gophers/gophers-6/main.go and appengine_flexible/analytics/analytics.go, too?

Definitely! Not sure I missed them initially. Must have grepped inside of getting-started.

[tbpg]

Thanks! Will wait for tests then merge.