Packaging for the v3.4.0 (shotgunsoftware#306)

Packaging for release v3.3.6 (shotgunsoftware#286)

* Packaging for v3.3.6

* Bump version to v3.3.6.dev

* Bump version to v3.3.6.dev

* Update version strings

Updates documentation about setting up environment, Python version re…

…quirements and Shotgun to ShotGrid renaming.

Retries on 503, Updates Python 3.9 docs and CI and Fixes git protocol…

… for installation

Replacing shotgunsoftware urls with Autodesk Knowledge Network and Sh…

…otGrid Developer Documentation pages.

Updates version of httplib2.

Retries on 502.

Updates version to 3.3.0.

Bundles certifi and uses this for the certificates.

SG-17710: update task dependencies section (shotgunsoftware#232)

* SG-17710: update task dependencies section

* SG-17710: fixes based on review comments

Co-authored-by: Vladimir Gusarov <vladimir.gusarov@autodesk.com>