update dependabot.yml to run against development not dev - remove v6 references

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

.github/dependabot.yml

@@ -7,7 +7,7 @@ updates:
       interval: "weekly"
       day: saturday
       time: "10:00"
-    target-branch: dev
+    target-branch: development
     reviewers:
       - "pi-hole/docker-maintainers"
   - package-ecosystem: "docker"
@@ -16,7 +16,7 @@ updates:
       interval: "weekly"
       day: saturday
       time: "10:00"
-    target-branch: dev
+    target-branch: development
     reviewers:
       - "pi-hole/docker-maintainers"
   - package-ecosystem: pip
@@ -26,35 +26,6 @@ updates:
       day: saturday
       time: "10:00"
     open-pull-requests-limit: 10
-    target-branch: dev
-    reviewers:
-      - "pi-hole/docker-maintainers"
-  # Maintain dependencies for GitHub Actions development-v6
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-      day: saturday
-      time: "10:00"
-    target-branch: development-v6
-    reviewers:
-      - "pi-hole/docker-maintainers"
-  - package-ecosystem: "docker"
-    directory: "/src/"
-    schedule:
-      interval: "weekly"
-      day: saturday
-      time: "10:00"
-    target-branch: development-v6
-    reviewers:
-      - "pi-hole/docker-maintainers"
-  - package-ecosystem: pip
-    directory: "/test"
-    schedule:
-      interval: weekly
-      day: saturday
-      time: "10:00"
-    open-pull-requests-limit: 10
-    target-branch: development-v6
+    target-branch: development
     reviewers:
       - "pi-hole/docker-maintainers"