Lock file maintenance

Update dependency poetry to v1.6.1

Merge pull request #230 from sbrunner/update-python

Use Python 3.9

Merge pull request #213 from sbrunner/renovate/poetry

Update dependency poetry to v1.5.1

Merge pull request #182 from sbrunner/poetrty-1-4

Upgrade to Poetry 1.4

Fix publish

Merge pull request #145 from sbrunner/renovate/poetry

Update dependency poetry to v1.3.1

Merge pull request #112 from sbrunner/poetry-core-constraint

Add constraint to Poetry core

Merge pull request #109 from sbrunner/renovate/patch-all-patch-versions

Update dependency c2cciutils to v1.3.10

Merge pull request #78 from sbrunner/fix

Fix the upgrade to Poetry 1.2