Re-adds use mamba

Author: tebjan

.github/workflows/build-wheels-cuda.yaml

@@ -64,6 +64,7 @@ jobs:
           activate-environment: "build"
           python-version: ${{ matrix.pyver }}
           miniforge-version: latest
+          use-mamba: true
           add-pip-as-python-dependency: true
           auto-activate-base: false