move to latest selenium image

This could go too far the opposite direction, but I'd rather see
failures because of selenium updates than get a false sense of security
from being on an older version.

Consumers of widgetastic will want to be on the latest version of
selenium

.github/workflows/test_suite.yml

@@ -14,15 +14,15 @@ jobs:
   tests:
     # Run unit tests on different version of python and browser
     name: 🐍 Python-${{ matrix.python-version }}-${{ matrix.browser }}
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     strategy:
       matrix:
         browser: [chrome, firefox]
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
 
     steps:
       - name: Pull selenium-standalone:latest
-        run: podman pull selenium/standalone-${{ matrix.browser }}:4.9
+        run: podman pull selenium/standalone-${{ matrix.browser }}:latest
 
       - name: Pull docker.io/library/nginx:alpine
         run: podman pull docker.io/library/nginx:alpine