docs: Update readme to remove references around 3.5

[marcelwgn]

GitHub Issue (If applicable): #50

PR Type

What kind of change does this PR introduce?

• Documentation content changes

What is the current behavior?

Readme includes comments talking about 3.5 which has been released for a few months now.

What is the new behavior?

Comments are no longer present as they are not relevant anymore.

Closes #50

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] Tests for the changes have been added (for bug fixes / features) (if applicable)
• [x] Contains NO breaking changes
• [x] Associated with an issue (GitHub or internal)

Other information

Internal Issue (If applicable):

[jeromelaban]

Uno needs to be updated in the solution, will do in a separate PR (related to VS 16.10)

[jeromelaban]

/azp run

[azure-pipelines[bot]]

Azure Pipelines successfully started running 1 pipeline(s).

[jeromelaban]

Thanks for your contribution!