Remove default conda channels from CI

.github/workflows/httomo_docs.yml

@@ -25,11 +25,12 @@ jobs:
             python-version: '3.10'
 
         - name: httomo-docs
-          uses: conda-incubator/setup-miniconda@v2
+          uses: mamba-org/setup-micromamba@v2
           with:
-            auto-update-conda: false
-            activate-environment: httomo-docs
+            environment-name: httomo-docs
             environment-file: ./docs/source/doc-conda-requirements.yml
+            post-cleanup: 'all'
+            init-shell: bash
 
         - name: Install httomo-backends
           run: |

.github/workflows/httomo_version_tag.yml

@@ -27,12 +27,18 @@ jobs:
         with:
           python-version: '3.11'
 
-      # install dependencies with conda
-      - name: Install dependencies with conda
+      # setup conda
+      - name: Setup conda
+        uses: mamba-org/setup-micromamba@v2
+        with:
+          post-cleanup: 'all'
+          init-shell: bash
+
+      # install dependencies
+      - name: Install dependencies
         run: |
-          $CONDA/bin/conda install -c conda-forge conda-build
-          $CONDA/bin/conda install -c conda-forge anaconda-client
-          $CONDA/bin/conda list
+          micromamba install -c conda-forge conda-build anaconda-client
+          micromamba list
 
       - name: Decrypt a secret
         run: ./.scripts/decrypt_secret.sh