ci.yml - drop installation of libffi7

Not sure if necessary for anything but rigetti.

Author: pavoljuhas

.github/workflows/ci.yml

@@ -201,10 +201,6 @@ jobs:
           cache-dependency-path: |
             **/requirements.txt
             dev_tools/requirements/**/*.txt
-      - name: Install system packages
-        run: |
-          sudo apt-get update
-          sudo apt-get install libffi7
       - name: Install requirements
         run: |
           pip install --upgrade setuptools wheel
@@ -231,10 +227,6 @@ jobs:
           cache-dependency-path: |
             **/requirements.txt
             dev_tools/requirements/**/*.txt
-      - name: Install system packages
-        run: |
-          sudo apt-get update
-          sudo apt-get install libffi7
       - name: Install requirements
         run: |
           pip install wheel
@@ -296,9 +288,6 @@ jobs:
             **/requirements.txt
             dev_tools/requirements/**/*.txt
       - name: Install system requirements
-        run: |
-          sudo apt-get update
-          sudo apt-get install libffi7
       - name: Install requirements
         run: |
           pip install --upgrade setuptools wheel