[FIX] reqs.txt: bump psutil from 5.5.1 to 5.6.6
[FIX] reqs.txt: bump psutil from 5.5.1 to 5.6.6

Bumps [psutil](https://github.com/giampaolo/psutil) from 5.5.1 to 5.6.6.
- [Release notes](https://github.com/giampaolo/psutil/releases)
- [Changelog](https://github.com/giampaolo/psutil/blob/master/HISTORY.rst)
- [Commits](https://github.com/giampaolo/psutil/compare/release-5.5.1...release-5.6.6)

The only API-incompatible change in 5.6 is the removal of memory_maps() on
OSX, which we aren't relying on at this point:
  https://github.com/giampaolo/psutil/blob/master/HISTORY.rst#560

closes odoo/odoo#47632

Original-signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
X-original-commit: a6026a4fc47421b1c4a1a8e42b3f56ab61027209
Signed-off-by: Olivier Dony (odo) <d670d44c3ca8bd4cd53a3b09f8bf8fc35e4843cc@openerp.com>

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo