PPO cpp project

[Antymon]

Adding personal project dependant on Stable Baselines to the docs (link).

Description

Motivation and Context

• I have raised an issue to propose this change (required for new features and bug fixes)

closes #513

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)

Checklist:

• I've read the CONTRIBUTION guide (required)
• I have updated the changelog accordingly (required).
• My change requires a change to the documentation.
• I have updated the tests accordingly (required for a bug fix or a new feature).
• I have updated the documentation accordingly.
• I have ensured pytest and pytype both pass.

[araffin]

Hello,
Thanks for the PR, please don't forget the changelog.
Btw, it seems that this is related to #513 , so you can also update this section of the doc ;)

[Antymon]

Oh, I could expand that section on C++, but it would quickly boil down to saying it will require some work of you if you want to do it and pointing at my work as an example.

[araffin]

Oh, I could expand that section on C++, but it would quickly boil down to saying it will require some work of you if you want to do it and pointing at my work as an example.

Sounds good, this is only meant to provide starter material (not complete tutorial) for someone who wants to export his model to C++.

[Antymon]

I resolved changelog conflicts.
I understand that C++ portability suggestions are out of scope of this PR.

[araffin]

Please still put a link to your project in the export model section ;) (plus one or two sentences)

[Antymon]

Here you go.

[araffin]

LGTM, merci beaucoup =) (those kind of contribution are really helpful)

[araffin]

I bypassed Codacy because no changes to the code were made.