Update the changelog

[antonwolfy]

The PR populates the changelog with 0.18.1 release, adds missing chnages, bumps changelog format version to 1.1.0, and changes date format to the recommended one.

• Have you provided a meaningful PR description?
• Have you added a test, reproducer or referred to an issue with a reproducer?
• Have you tested your changes locally for CPU and GPU devices?
• Have you made sure that new changes do not introduce compiler warnings?
• Have you checked performance impact of proposed changes?
• Have you added documentation for your changes, if necessary?
• Have you added your changes to the changelog?

[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/index.html

[github-actions]

Array API standard conformance tests for dpnp=0.19.0dev0=py312h509198e_25 ran successfully.
Passed: 1231
Failed: 0
Skipped: 9

[coveralls]

coverage: 71.863%. remained the same
when pulling 55c6fa3 on populate-changelog
into 278cf42 on master.