Update opentelemetry-proto submodule to version from May 18, 2021

[maxgolov]

Update opentelemetry-proto submodule from 5 months old to latest version:

commit 795cc815ce9bb438b46a4a7f6ecb465b52d50935 (HEAD -> main, origin/main, origin/HEAD)
Author: Bogdan Drutu <bogdandrutu@gmail.com>
Date:   Tue May 18 14:42:43 2021 -0700

No other code changes.

[codecov]

Codecov Report

Merging #825 (60c77e8) into main (93dd39b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #825   +/-   ##
=======================================
  Coverage   95.52%   95.52%           
=======================================
  Files         156      156           
  Lines        6618     6618           
=======================================
  Hits         6321     6321           
  Misses        297      297           

[ThomsonTan]

Is it more conservative to snap the latest tag instead of main branch?

[maxgolov]

Is it more conservative to snap the latest tag instead of main branch?

My understanding is it's generally both safer and more predictable to track to specific commit. And the usual flow is:

cd submodule
git pull
cd ..
git add submodule
git commit -m "Updated version to X"

This guarantees that by default when you perform recursive cloning, you get a set of deps, a baseline that is guaranteed to work / passes CI. It would've been a bit less predictable if we automated that process to automagically update whenever there's a new commit in the proto repo ( we could, but I don't think we should ).

[lalitb]

Thanks for the update. Should we also update the proto package used by bazel as part of this PR:

opentelemetry-cpp/bazel/repository.bzl

Line 48 in 93dd39b

strip_prefix = "opentelemetry-proto-0.6.0",

[lalitb]

Merging now. For bazel, we can do it in separate PR.