chore/bump oa 0.3.1

[0xArdi]

This PR bumps the repo to open-autonomy@v0.3.1 and open-aea@1.20.0.

[0xArdi]

python/mypy#13627
Pinning to py3.10.6 to avoid the static checks failing.
The ultimate fix should use a version of mypy that doesn't have this issue.

[DavidMinarsch]

Why so explicit? I think we shouldn't do that

[dvilelaf]

I think it has to do with this.

It's not architecture dependent, it's only about the specific version of Python you have in your image. If you have Python 3.10.7 you'll see the error, if you have Python 3.10.6 you won't. In all cases, upgrading to mypy 0.981 will fix.

I can reproduce the problem locally when running tox -e mypy.

[DavidMinarsch]

You should also update this to the matching hashes here: https://github.com/valory-xyz/open-autonomy/blob/v0.3.1/packages/packages.json

[0xArdi]

The hashes are correct, and that is on accident.
What happened is I had #27 and #29 on my local. As I was bumping to v0.3.1 I needed to add a fix to #27, the local packages were from v0.3.1 and were updated when I ran make generators.