Add sponsors europython 2020

[mjmolina]

This PR is not 100% complete. All the sponsorship levels are "Unknown" values.

[hypha]

2020 (Remote):

• Keystone: 12.5K
• Diamond: 7.5K
• Platinum: 5K
• Gold: 3K
• Silver: 2K
• Bronze: 1.25K
• Patron: 0.75K

[mjmolina]

Thanks a lot for your help @hypha <3 !
A side of this information we would need the level info.

Example:
name: "This is an example Company", level : Platinium

Current status:

"sponsors": [
        {
            "name": "This is an example Company",
            "website": "https://example....",
            "level": "Unknown"
        }
        ,...