[EXPORTER] Change OTLP HTTP content_type default to binary

[kkuehl]

https://github.com/open-telemetry/opentelemetry-proto/blob/main/docs/specification.md

Fixes # (issue)

Changes

Please provide a brief description of the changes here.

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[linux-foundation-easycla]

• ❌ - login: @kirby-mimic / name: kirby@mimic.com . The commit (cb937db, ba5f22e, 97c6120, 3d4eadd, d7168ce) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[ThomsonTan]

@kkuehl thanks for the contribution. Could you please sign the CLA?

[lalitb]

Thanks for working on it. Also, please add the changelog as this is supposed to be a breaking change.

[kkuehl]

@kkuehl thanks for the contribution. Could you please sign the CLA?

I have signed the CLA (twice now), but I assume there is a manual step?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (f084fbc) 87.06% compared to head (d7168ce) 87.04%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2480      +/-   ##
==========================================
- Coverage   87.06%   87.04%   -0.01%     
==========================================
  Files         199      199              
  Lines        6087     6087              
==========================================
- Hits         5299     5298       -1     
- Misses        788      789       +1     

see 1 file with indirect coverage changes

[marcalff]

Thanks for the patch.

The spec does not say (unless I missed it) to use binary of json by default,
what is the motivation for this change ?

[marcalff]

/easycla

[marcalff]

@kkuehl

About the CLA, somehow the system sees two accounts : @kkuehl and @kirby-mimic

Please make sure you sign the CLA for the proper account.

This needs to be resolved, as we can not merge a PR without it.

Start over and create another clean PR if you have to.