Bump conda-incubator/setup-miniconda from 2 to 3

Bumps [conda-incubator/setup-miniconda](https://github.com/conda-incubator/setup-miniconda) from 2 to 3.
- [Release notes](https://github.com/conda-incubator/setup-miniconda/releases)
- [Changelog](https://github.com/conda-incubator/setup-miniconda/blob/main/CHANGELOG.md)
- [Commits](conda-incubator/setup-miniconda@v2...v3)

---
updated-dependencies:
- dependency-name: conda-incubator/setup-miniconda
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/testing.yml

@@ -24,7 +24,7 @@ jobs:
           fetch-depth: 0
 
       - name: Set up Miniconda
-        uses: conda-incubator/setup-miniconda@v2
+        uses: conda-incubator/setup-miniconda@v3
         with:
           auto-update-conda: true
           python-version: ${{ matrix.python-version }}