ci: switch to python 3.10, use ubuntu-22.04 for python 3.7

Author: foosel

.github/workflows/build.yml

@@ -13,10 +13,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: 🏗 Set up Python 3.7
+      - name: 🏗 Set up Python 3.10
         uses: actions/setup-python@v4
         with:
-          python-version: 3.7
+          python-version: "3.10"
       - name: 🏗 Install build dependencies
         run: >-
           python -m pip install wheel --user
@@ -50,7 +50,7 @@ jobs:
     strategy:
       matrix:
         python: ["3.7", "3.8", "3.9", "3.10"]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04 # change back to ubuntu-latest once we drop Python 3.7
     steps:
       - uses: actions/checkout@v4
       - name: 🏗 Set up Python ${{ matrix.python }}