Update ci_backends.yml

Author: ohuettenhofer

.github/workflows/ci_backends.yml

@@ -28,11 +28,12 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install -r requirements.txt
+        ver=$(python -c "import sys; print(sys.version_info.minor)")
         if [ $ver -eq 7 ]; then
             # myqlm does not work in python3.7
             pip install "cirq" "qiskit>=0.30" "qulacs" "qibo==0.1.1"
         elif [ $ver -eq 9 ]; then
-            pip install "cirq" "qiskit" "qulacs" "qibo==0.1.1" "myqlm" "cirq-google"
+            pip install "cirq" "qiskit" "qiskit-aer" "qulacs" "qibo" "myqlm" "cirq-google"
         fi
         pip install -e .
     - name: Lint with flake8