chore: Group dependabot updates

Run dependabot updates weekly instead of daily, and group them together
for the different providers (GitHub Actions and pip), to reduce the
amount of noise in the repository history.

.github/dependabot.yml

@@ -3,24 +3,23 @@ updates:
   - package-ecosystem: github-actions
     directory: /
     schedule:
-      interval: daily
+      interval: weekly
+    groups:
+      github-actions-dependencies:
+        applies-to: version-updates
+        patterns:
+          - "*"
 
   - package-ecosystem: pip
-    directory: /doc
+    directories:
+      - /
+      - /doc
+      - /example
+      - /test
     schedule:
-      interval: daily
-
-  - package-ecosystem: pip
-    directory: /example
-    schedule:
-      interval: daily
-
-  - package-ecosystem: pip
-    directory: /
-    schedule:
-      interval: daily
-
-  - package-ecosystem: pip
-    directory: /test
-    schedule:
-      interval: daily
+      interval: weekly
+    groups:
+      python-dependencies:
+        applies-to: version-updates
+        patterns:
+          - "*"