Update Doc for aws propagator default sampling behavior

[NathanielRN]

Description

By default the TraceProvider uses a Sampler which respects the Parent Sampling decision. If the user does not provide Sampled=1; into their X-Amzn-Trace-Id header when using the AwsXrayFormat propagator, the parent context (and all subsequent child spans) are assumed to be sampled=false by default.

This PR updates the docs to warn users about that.

Fixes #649

Type of change

Please delete options that are not relevant.

• This change requires a documentation update

How Has This Been Tested?

N/A

Does This PR Require a Core Repo Change?

• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
  - [ ] Changelogs have been updated
  - [ ] Unit tests have been added
• Documentation has been updated

[owais]

Can you review your own PR? :) @NathanielRN ?

[NathanielRN]

Ah that's a good point @owais 🙃 That's probably why the CODEOWNERS reviewer didn't work 😅 I'll close this then 🙂

[owais]

I can still merge it for you as a maintainer if you re-open

[owais]

Until update the check to only require it if you are not the author or add another AWS person as codeowner on your recommendation.

[NathanielRN]

Thanks a ton for that! 😄 I think I can get a colleague at AWS to open the PR for me so we can test the CODEOWNER action out, but I appreciate your help with this! 🙂

[NathanielRN]

@lzchen An update on the CODEOWNERS action. With the change in #659 I will now get assigned even if I am the one who opened the PR (I still can't review though). However, I noticed that if I try to amend a commit, the "Component Owner" action fails as seen on this workflow.

I filed this issue on the action repo and mentioned that maybe the solution is to not run on the pull_request_target -> synchronize activity (which is a default activity of the GitHub event).