Bump mamba-org/setup-micromamba from 2 to 3

Bumps [mamba-org/setup-micromamba](https://github.com/mamba-org/setup-micromamba) from 2 to 3.
- [Release notes](https://github.com/mamba-org/setup-micromamba/releases)
- [Commits](mamba-org/setup-micromamba@v2...v3)

---
updated-dependencies:
- dependency-name: mamba-org/setup-micromamba
  dependency-version: '3'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -55,7 +55,7 @@ jobs:
           sed -i -e "s/- python=.*/- python=$PYTHON_VERSION/g" environment.yml
 
       - name: Setup Mamba
-        uses: mamba-org/setup-micromamba@v2
+        uses: mamba-org/setup-micromamba@v3
         with:
           environment-file: environment.yml
           cache-environment: true