Allow requests-toolbelt 0.10.* releases (#6924)

requests-toolbelt has released 0.10.0 and 0.10.1 recently. These don't
look to make any backwards-incompatible changes (they only add features)
so poetry should be able to work with them fine.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

# Pull Request Check List

Resolves: #6922

- [-] Added **tests** for changed code.
- [-] Updated **documentation** for changed code.

Signed-off-by: Adam Williamson <awilliam@redhat.com>