copyright: update all copyright lines and remove year

[elevran]

According to https://hynek.me/til/copyright-years/ and linked sources (including Linux Foundation) copyright years:

• are mostly pointless in all major jurisdictions
• are already dropped by many big corporations and projects
• cause pointless churn on every January and git already keeps history for us...

the years range (2022-present) is kept in LICENSE. The copyright in .licenserc.yaml is updated accordingly.

Fixes #285