Add first documentation redirection

[Yoann-Abbes]

What does this PR do?

We have a blank page when hitting https://next-docs.kuzzle.io/sdk/go/3/
This PR adds a redirection

How should this be manually tested?

• Step 1 :
• Step 2 :
• Step 3 :
  ...

Other changes

Boyscout

[codecov]

Codecov Report

Merging #294 (fd202f4) into 3-dev (72f89b4) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##            3-dev     #294   +/-   ##
=======================================
  Coverage   89.74%   89.74%           
=======================================
  Files         242      242           
  Lines        4045     4045           
=======================================
  Hits         3630     3630           
  Misses        365      365           
  Partials       50       50           

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[rolljee]

https://deploy-preview-294--doc-sdk-go.netlify.app/, we are correctly redirected 👍