[BUILD] Fix benchmark CI

[esigo]

Fixes benchmark CI

Changes

Uses g++-10 in ubuntu latest
tested 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

[lalitb]

This looks good, thanks - we can later also try with default compiler ( g++-11 ) on ubuntu-latest, with latest version of google benchmark v1.7.1 :)

[codecov]

Codecov Report

Merging #1808 (7bc09a8) into main (e1b5611) will increase coverage by 0.04%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1808      +/-   ##
==========================================
+ Coverage   85.73%   85.77%   +0.04%     
==========================================
  Files         171      171              
  Lines        5240     5240              
==========================================
+ Hits         4492     4494       +2     
+ Misses        748      746       -2     

Impacted Files	Coverage Δ
...include/opentelemetry/sdk/common/circular_buffer.h	98.00% <0.00%> (-2.00%)	⬇️
ext/src/http/client/curl/http_client_curl.cc	81.44% <0.00%> (+1.14%)	⬆️