Rename development branch to dev, update dependabot.yml

Dropped partially broken rebase and merge CI

Bug: #286
Change-Id: I16f8b8ecac0d6b18f28dfc15c238d9b9a3256652

Author: winstonsung

.github/dependabot.yml

@@ -6,10 +6,10 @@ updates:
     schedule:
       interval: "daily"
     open-pull-requests-limit: 10
-    target-branch: "development"
+    target-branch: "dev"
   - package-ecosystem: "pip"
     directory: "/"
     schedule:
       interval: "daily"
     open-pull-requests-limit: 10
-    target-branch: "development"
+    target-branch: "dev"