group dependabot updates weekly and per ecosystem (#51)

Signed-off-by: laurentsimon <laurentsimon@google.com>

.github/dependabot.yml

@@ -13,12 +13,21 @@
 # limitations under the License.
 
 version: 2
+# See https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file.
 updates:
   - package-ecosystem: "pip"
     directory: "/"
     schedule:
-      interval: "daily"
+      interval: "weekly"
+    groups:
+      all:
+        patterns:
+        - "*"
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
-      interval: "daily"
+      interval: "weekly"
+    groups:
+      all:
+        patterns:
+        - "*"