chore: remove python3.7 and python3.8 to get through ci

Because python 3.7 and 3.8 aren't bundled with ubuntu 24.04 we
remove for the sake of seeing if CI passes otherwise. We will add back
in in other ways if it doesn't.

.github/workflows/on-pull-request.yml

@@ -9,11 +9,8 @@ jobs:
     runs-on: ubuntu-24.04
     strategy:
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.9", "3.10", "3.11"]
         new-python-protobuf: ["true"]
-        include:
-          - python-version: "3.7"
-            new-python-protobuf: "false"
 
     env:
       TEST_API_KEY: ${{ secrets.ALPHA_TEST_AUTH_TOKEN }}
@@ -67,10 +64,6 @@ jobs:
       matrix:
         # TODO: one of the examples dependencies does not support 3.11
         include:
-          - python-version: "3.7"
-            package: prepy310
-          - python-version: "3.8"
-            package: prepy310
           - python-version: "3.9"
             package: prepy310
           - python-version: "3.10"