Upgrade to the API v0.18.x

[llucax]

What's needed?

We need to upgrade to use the new v0.18.x API version.

Proposed solution

Follow upgrade steps in:

• https://github.com/frequenz-floss/frequenz-api-microgrid/releases/tag/v0.18.0

Additional context

We need to watch out for changes in v0.16.x and v0.17.x too:

• https://github.com/frequenz-floss/frequenz-api-microgrid/releases/tag/v0.16.0
• https://github.com/frequenz-floss/frequenz-api-microgrid/releases/tag/v0.17.0