[Event Hubs] Ship 2.1.0 to release features that were made in master branch prior to Track 2

[ramya-rao-a]

The proxy support and the fix for #3240 has been in the master branch for a while now, but has not been shipped yet. We also have the ongoing browser support work. All 3 of these features/bug-fixes can be shipped independent of the track 2 work that is happening in parallel.

This way we have a chance to get user feedback on proxy and browser support from a larger audience than the preview audience

This issue is to track the work needed to ship version 2.1.0 of Event Hubs library after the below are complete

• Proxy support (changes are in master branch)
• Fix for bug [Event Hubs] No default export for async-lock #3240 (changes are in master branch)
• revert any changes that can be considered as breaking changes [Event Hubs] Revert breaking changes in order to release 2.1.0 #3301
• Browser support [Event Hubs] Add tests for browser mode #2809
• Throw error when createFromAadCredentials is used in browser mode as we can't support that. [Event Hubs] Throw error when createFromAadCredentials is used in browser mode as we can't support that. #3588
• Update date in changelog to the date of release (done with [Event Hubs] Simplify messaging around Websockets #3422)

[ramya-rao-a]

With #2809 hitting blockers, we will not be able to ship the browser support any time soon. Therefore, we will be shipping what we have i.e proxy support and fix for #3240 in 2.1.0 instead

[ramya-rao-a]

Closing as we have shipped 2.1.0 of Event Hubs today