Set cplex as the first optioanl solver to install

Author: jinningwang

.github/workflows/codecov.yml

@@ -32,7 +32,7 @@ jobs:
       name: Try installing optional packages
       run: |
         # Try installing one of the optional packages
-        pip install Mosek || pip install gurobipy || pip install coptpy || pip install xpress || pip install cplex || echo "All optional packages failed to install. Skipping."
+        pip install cplex || pip install gurobipy || pip install xpress || echo "All optional packages failed to install. Skipping."
 
     - shell: bash -el {0}
       name: Run pip check

.github/workflows/publish-pypi.yml

@@ -28,7 +28,7 @@ jobs:
       name: Try installing optional packages
       run: |
         # Try installing one of the optional packages
-        pip install Mosek || pip install gurobipy || pip install coptpy || pip install xpress || pip install cplex || echo "All optional packages failed to install. Skipping."
+        pip install cplex || pip install gurobipy || pip install xpress || echo "All optional packages failed to install. Skipping."
     - shell: bash -el {0}
       name: Run pip check
       run: |