Conform to naming standard in precice/tutorials

[IshaanDesai]

precice/tutorials#699 triggers this change. The Micro Manager writes two data via preCICE: Active-State and Active-Steps, which are written by the tutorial case that uses the Micro Manager. Therefore, this data needs to conform to the tutorials' naming standard.

Checklist:

• I added a summary of the changes (compared to the last release) in the CHANGELOG.md.
• If necessary, I made changes to the documentation and/or added new content.
• I will remember to squash-and-merge, providing a useful summary of the changes of this PR.