Amend an expired link in doc

[ebi-yade]

Hello, maintainer-san! 👋🏽

I hope you're having a great day! While browsing through the repository, I noticed that there's an expired link in the documentation. It seems that the client example has been moved to the Contrib package.

As a reference, you can find the related Pull Request in both repositories:

• Remove othttp and httptrace instrumentations that have moved to contrib open-telemetry/opentelemetry-go#1032
• Add instrumentation for net/http and net/httptrace open-telemetry/opentelemetry-go-contrib#190

Thank you for your attention and assistance!

[punya]

/gcbrun

[codecov]

Codecov Report

Merging #628 (ac2083f) into main (327f586) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #628   +/-   ##
=======================================
  Coverage   66.25%   66.25%           
=======================================
  Files          36       36           
  Lines        4264     4264           
=======================================
  Hits         2825     2825           
  Misses       1312     1312           
  Partials      127      127           

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