Cannot build due to breaking, non-semver update to Flatbuffer

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Flatbuffers should be pinned to 0.8.4, due to a breaking change in 0.8.5:
google/flatbuffers#6600

Reporter: ii

_{Note: This issue was originally created as ARROW-12623. Please see the migration documentation for further details.}

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Micah Kornfield / @emkornfield:
@alamb [~andygrove73]  is there an established pattern for tracking straggler Rust issues on JIRA?

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Andrew Lamb / @alamb:
Thanks for bringing this to our attention @emkornfield. There is no established pattern and I plan to do this manually

[~xog] we have fixed this in arrow-rs in apache/arrow-rs#238

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Andrew Lamb / @alamb:
Moved to github issues apache/arrow-rs#238 (which has also since been fixed)

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Todd Farmer / @toddfarmer:
Transitioning issue from Resolved to Closed to based on resolution field value.