style: pyupgrade 3.9

[jkowalleck]

• followup of feat!: drop support for Python <3.9 #809
• add pyupgrade tooling and tests
• apply pyupgraded code style

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ +0.00%	✅ 100.00% (target: 80.00%)

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (8ac09b6)	5203	4875	93.70%
Head commit (71dcac2)	5203 (+0)	4875 (+0)	93.70% (+0.00%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#822)	3	3	100.00%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

See your quality gate settings    Change summary preferences