Docs: Update events page with upcoming events

[brandonroberts]

Past events are listed in upcoming events. Some upcoming events are missing also

• Angular Connect
• Angular Denver
• Component.tech
• NG-MY
• ngRome
• ngVikings
• NG-MY
• Open Source 101
• Refactr.Tech

Other people speaking about NgRx at some event are welcome to add theirs also.

[santoshyadavdev]

Hi @brandonroberts ,
Let me know i can take it.

[itayod]

Angular Up