Add a copyright / notice file

[davidmateos]

Please answer these questions before submitting a bug report.

What version of OpenCensus are you using?

OpenCensus Go 0.22.5

What version of Go are you using?

1.15

What did you do?

N/A

What did you expect to see?

This project doesn't appear to include any copyright information or a NOTICE file. This is desired to comply with the open source license conditions.

What did you see instead?

LICENSE file contains the placeholder for year and copyright owner ("Copyright [yyyy] [name of copyright owner]")

Additional context

Add any other context about the problem here.

[nikzayn]

@davidmateos I would like to take this up. Just a heads up, I will like to know that do I need to update the placeholder for year and copyright owner or do I need to do something else.

[davidmateos]

It's enough if you update the placeholder for year and copyright owner