Bump mamba-org/setup-micromamba from 2 to 3 (#205)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/unit_tests.yml

@@ -79,7 +79,7 @@ jobs:
         with:
           qt: true
           pyvista: false
-      - uses: mamba-org/setup-micromamba@v2
+      - uses: mamba-org/setup-micromamba@v3
         with:
           environment-file: environment.yml
           create-args: >- # beware the >- instead of |, we don't split on newlines but on spaces