When exporting to a tarfile, we first export each module's translations
to a file on the FS, then create a tarball from all of them.
With the P3 bytes/string split, translation export was defined to export
to a bytes IO object in order to work correctly with CSV (which work on
bytes IO for better cross-version compatibility). However the tgz file
export was left opening module's files in `w` mode, which in P3 means
text, which blows up as POFile expects to ultimately write to a bytes IO
object: it uses text, and a StreamReaderWriter is used to translate that
into an underlying bytes IO.
Fix by explicitly opening the files in binary mode.
Fixes#22700
xmo-odoo
43617bbcb6