Add a "what's new" page

[brendanzagaeski]

This is a rough candidate idea for a possible way to list product announcements in this repository. It's totally open to brainstorming, requests, or suggestions for adjustments.

If I understood correctly, I think the intention is that this list doesn't need to be limited to larger new features. It can also include smaller changes that might not have much representation elsewhere.

I borrowed a couple items from the AzureRedis Twitter feed to have some concrete examples to look at. I added some documentation links to the text. Maybe for these larger feature announcements, linking to relevant blog posts is desirable too? Thinking out loud, even if we add another page that specifically aggregates blog posts, I think it would be fine to include the links to the blog posts for larger feature announcements on both pages.

[brendanzagaeski]

Changes in the latest force-push:

Add private link GA announcement.

[brendanzagaeski]

Additional note, partly for my own future reference:

While I was checking to make sure I copied the private link text accurately, I learned about another place these feature-sized announcements appear: https://azure.microsoft.com/updates/?query=Azure%20Cache%20for%20Redis

Each of the entries there has a link to a paragraph with a bit more information.

[brendanzagaeski]

Changes in the latest force-push:

Remove the days of the week from the dates. That looks clearer to me for viewing the history of the list. Admittedly, for new items, this might make it a little trickier to spot what's new, so maybe there can be a "new this month" section too.

[brendanzagaeski]

Changes in the latest force-push:

• Related to the last few comments in this PR discussion, add a "Current preview features" section to help identify features that are not yet in GA.
• Update the title of the page to "What's new Azure Cache for Redis." Carolina had a good suggestion that a title like this will give the page a more friendly, less formal tone.
• Based on another good suggestion from Carolina, include a bold update note for the Redis 6.0 preview to highlight that the GA is coming soon and developers can start planning app updates accordingly.

Possible question:

Does it sound OK to say "The target for GA is summer 2021" for Redis 6.0? Or is it preferable not to mention a specific timeline at all?

Comparing to another Azure service would probably be best, but just for one quick point of comparison, for Visual Studio, the earlier format in vs2019-roadmap included the estimated quarter of the year, but the newer format in vs-roadmap doesn't mention any specific timelines.

[brendanzagaeski]

Alternative layout idea, condensing the preview section and shortening the heading names, maybe worth it to make the page easier to skim: