group dependency updates to avoid PR spam

Author: pk910

.github/dependabot.yml

@@ -5,8 +5,16 @@ updates:
     schedule:
       interval: "weekly"
     open-pull-requests-limit: 10
+    groups:
+      "Server dependencies":
+        patterns:
+          - "*"
   - package-ecosystem: "npm"
     directory: "/faucet-client"
     schedule:
       interval: "weekly"
     open-pull-requests-limit: 10
+    groups:
+      "Client dependencies":
+        patterns:
+          - "*"