Support waitForCompletion in cfInvalidate

[alexey-pelykh]

• Please check if the PR fulfills these requirements

• The commit message describes your change
• Tests for the changes have been added if possible (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Changes are mentioned in the changelog (for bug fixes / features)

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Minor feature of waitForCompletion in cfInvalidate

• What is the current behavior? (You can also link to an open issue here)

Currently invalidation is only enqueued and current log is misleading

• What is the new behavior (if this is a feature change)?

It's a non-breaking-change, by default behaviour is the same, but log message is modified.

• Does this PR introduce a breaking change? (What changes might users need to make in their setup due to this PR?)

No

• Other information:

N/A

[hoegertn]

Great idea, but please use client.waiters().invalidationCompleted().run(...);

[alexey-pelykh]

Done

[rkul]

Could you tell me when this amazing feature will be released?

[hoegertn]

I will try to build a release by the end of the week.