Pin the version of path since 17.0 removed deprecated methods (#675)

[xtrusia]

(cherry picked from commit 0c02af33e7fd5a0434bcff17cdd793ef03b32a11) Signed-off-by: Seyeong Kim [email protected]

Description of change

#677

cherrypicking for 2.8

https://openstack-ci-reports.ubuntu.com/artifacts/6cf/926023/1/check/charm-build/6cfced2/job-output.txt

Checklist

• [x] Are all your commits [logically] grouped and squashed appropriately?
• [x] Does this patch have code coverage?
• [x] Does your code pass make test?