Refactor(keyboard-event): Replace keycode for keyboard events with key

[RudarDaman]

No description provided.

[googlebot]

We found a Contributor License Agreement for you (the sender of this pull request), but were unable to find agreements for all the commit author(s) or Co-authors. If you authored these, maybe you used a different email address in the git commits than was used to sign the CLA (login here to double check)? If these were authored by someone else, then they will need to sign a CLA as well, and confirm that they're okay with these being contributed to Google.
In order to pass this check, please resolve this problem and then comment @googlebot I fixed it.. If the bot doesn't comment, it means it doesn't think anything has changed.

ℹ️ Googlers: Go here for more info.

[crisbeto]

There are a few reasons why we haven't done this already ourselves and which will make these changes difficult to land:

1. It wasn't supported on all browsers that we support. I think this might not be an issue anymore.
2. It's a breaking change for anybody consuming the keycodes package.
3. From what I remember browsers aren't consistent between each other when it comes to the values that they return for key. E.g. most browsers return ArrowDown whereas IE and Edge return Down.

[jelbourn]

As outlined in our contributing guide, the first step in working on a large change like this is to open an issue for discussion. Going from there, we always start with a design document and design review with the team. We go through these steps to ensure that everything in the library meets our standards for accessibility, i18n, and consistency with the rest of the code-base.

For this particular issue, we've intentionally not made this change due to browser support concerns. See #7374

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}