[CI] C++/Java/Rust workflows should trigger on changes to Flight.proto #24499
Description
The Flight DoExchange format change caused Rust build failures (ARROW-8308). We would have caught these in the format change patch, but the Rust builds weren't triggered on changes to format/Flight.proto.
Reporter: Neal Richardson / @nealrichardson
Assignee: Neal Richardson / @nealrichardson
PRs and other links:
Note: This issue was originally created as ARROW-8309. Please see the migration documentation for further details.