v0.31.0

• Change the --file flag to --path and allow --path to take both files and directories, instead of just files with the old --file. This flag is used to filter the actual Protobuf files built under an input for most commands. You can now do for example buf generate --path proto/foo to only generate stubs for the files under proto/foo. Note that the --file flag continues to work, but prints a deprecation message.