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-additional.yaml

@@ -25,7 +25,7 @@ jobs:
           fetch-depth: 0 # Fetch all history for all branches and tags.
 
       - name: Create conda environment
-        uses: mamba-org/setup-micromamba@v2
+        uses: mamba-org/setup-micromamba@v3
         with:
           environment-name: min-version-policy
           micromamba-version: 'latest'

.github/workflows/ci.yaml

@@ -49,7 +49,7 @@ jobs:
         fi
 
     - name: Create conda environment
-      uses: mamba-org/setup-micromamba@v2
+      uses: mamba-org/setup-micromamba@v3
       with:
         environment-name: mplotutils-tests
         cache-downloads: true

.github/workflows/upstream-dev-ci.yaml

@@ -41,7 +41,7 @@ jobs:
         with:
           fetch-depth: 0 # Fetch all history for all branches and tags.
       - name: Set up conda environment
-        uses: mamba-org/setup-micromamba@v2
+        uses: mamba-org/setup-micromamba@v3
         with:
           environment-file: ci/requirements/environment.yml
           environment-name: mplotutils-tests