Schedule dependabot PyPI updates to be weekly, not daily (#1227)

* Schedule dependabot updates from PyPI to be weekly, not daily

Batch up these updates to make them less chatty and more manageable as discussed at #1226 (review)

https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#scheduleinterval

* Group all PyPI updates into a single larger pull request

.github/dependabot.yml

@@ -2,8 +2,12 @@ version: 2
 updates:
 - package-ecosystem: pip
   directory: "/requirements"
+  groups:
+       PyPI:
+          patterns:
+            - "*"  # Group all PyPI updates into a single larger pull request
   schedule:
-    interval: daily
+    interval: weekly
   open-pull-requests-limit: 99
 - package-ecosystem: github-actions
   directory: "/"