[16.0][FIX] base_report_to_printer: fix encoding

[jbaudoux]

In Python3, os.write requires bytes-like object

cc @lmignon @rousseldenis

[jbaudoux]

You're so quick :)

Test added, ready to merge

[lmignon]

/ocabot merge patch

[OCA-git-bot]

On my way to merge this fine PR!
Prepared branch 16.0-ocabot-merge-pr-342-by-lmignon-bump-patch, awaiting test results.

[OCA-git-bot]

@lmignon The merge process could not be finalized, because command git push origin 16.0-ocabot-merge-pr-342-by-lmignon-bump-patch:16.0 failed with output:

To https://github.com/OCA/report-print-send
 ! [rejected]        16.0-ocabot-merge-pr-342-by-lmignon-bump-patch -> 16.0 (fetch first)
error: failed to push some refs to 'https://***@github.com/OCA/report-print-send'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

[OCA-git-bot]

Congratulations, your PR was merged at d0723af. Thanks a lot for contributing to OCA. ❤️