Release v0.9.0

[araffin]

Description

Pip release for the bug fixes and before merging HER branch. Probably the last release before v1.0 =)

Motivation and Context

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

closes #173

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 reformatted the code using make format (required)
• I have checked the codestyle using make check-codestyle and make lint (required)
• I have ensured make pytest and make type both pass. (required)

Note: we are using a maximum length of 127 characters per line

[Miffyli]

Given that #175 is about docs/typing, should that be included here or will it take time before finishing? Other than that no comments and LGTM :)

[araffin]

Given that #175 is about docs/typing, should that be included here or will it take time before finishing?

I did not know how much time #175 would take me and it is mainly unrelated to the release (as it does not affect users).
So I will merge this one first (this will also allow to create a new section in the changelog)