Configure multiple events in the playground

Not sure if you're still accepting PRs on this repo, if not, no worries. Just thought it would be a fun thing to play with. Also thanks for the neat tool!

I've extended the "playground" page to allow for adding and configuring multiple events so that people can simulate a wider range of workflows (or see how one workflow behaves under different triggering events). New functionality is:

Adding more than one event in the playground.
Removing events in the playground
Setting event specific configuration:
- push
- branch name
- file paths
- pull_request
- branch name
- file paths
- action
- issues
- action
Copying event configuration to a query parameter (as per the workflow config)
Loading event configuration from a query parameter (as per the workflow config)

Typescript isn't my strongest language so please feel free to suggest improvements as well. Thanks

cschleiden / github-actions-hero

Configure multiple events in the playground #50