Use bash instead of micromamba-shell in build-gcpy-environment action

.github/workflows/build-gcpy-environment.yml
- Replace "micromamba-shell {0}" with "bash -el {0}" in the run steps,
  since do not use the micromamba-shell option.

Signed-off-by: Bob Yantosca <[email protected]>

.github/workflows/build-gcpy-environment.yml

@@ -11,7 +11,7 @@ on:
   pull_request:
     # The branches below must be a subset of the branches above
     branches: [ "main", "dev" ]
-    
+
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -26,9 +26,8 @@ jobs:
           init-shell: bash
           cache-environment: true
           post-cleanup: 'all'
-      - name: Import gcpy in micromamba environment (bash)
+      - name: Activate the GCPy environment
         run: python -c "import gcpy"
-        shell: bash -el {0}
       - name: Run custom command in micromamba environment
         run: python -m gcpy.examples.plotting.create_test_plot
-        shell: micromamba-shell {0}
+        shell: bash -el {0}