Update ci.yml

We only support 3.9+ now so remove old versions from CI and add in 3.11

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-latest ]
-        python: [ 3.7, 3.8, 3.9, "3.10" ]
+        python: [ 3.9, "3.10", 3.11 ]
     steps:
       - name: Checkout
         uses: actions/checkout@v2