chore: adds `website:dev` command to package.json

[cdrage]

Adds website:dev command to package.json

What does this PR do?

Very small nitpick!

I'd like to run yarn run website:dev to use docusaurus in dev mode / watch mode.

Screenshot/screencast of this PR

N/A

What issues does this PR fix or reference?

N/A

How to test this PR?

Run yarn run website:dev

Signed-off-by: Charlie Drage [email protected]