Stop maintaining version 1.9 and maintain version 1.12

Signed-off-by: zhzhuang-zju <m17799853869@163.com>

.github/dependabot.yml

@@ -17,6 +17,12 @@ updates:
   schedule:
     interval: weekly
 
+- package-ecosystem: docker
+  directory: /cluster/images/
+  target-branch: "release-1.12"
+  schedule:
+    interval: weekly
+
 - package-ecosystem: docker
   directory: /cluster/images/
   target-branch: "release-1.11"
@@ -28,9 +34,3 @@ updates:
   target-branch: "release-1.10"
   schedule:
     interval: weekly
-
-- package-ecosystem: docker
-  directory: /cluster/images/
-  target-branch: "release-1.9"
-  schedule:
-    interval: weekly

.github/workflows/ci-image-scanning-on-schedule.yml

@@ -27,7 +27,7 @@ jobs:
           - karmada-search
           - karmada-operator
           - karmada-metrics-adapter
-        karmada-version: [ release-1.11, release-1.10, release-1.9 ]
+        karmada-version: [ release-1.12, release-1.11, release-1.10 ]
     steps:
       - name: checkout code
         uses: actions/checkout@v4

.github/workflows/ci-schedule-compatibility.yaml

@@ -20,7 +20,7 @@ jobs:
       fail-fast: false
       matrix:
         kubeapiserver-version: [ v1.23.4, v1.24.2, v1.25.0, v1.26.0, v1.27.3, v1.28.0, v1.29.0, v1.30.0, v1.31.0 ]
-        karmada-version: [ master, release-1.11, release-1.10, release-1.9 ]
+        karmada-version: [ master, release-1.12, release-1.11, release-1.10 ]
     env:
       KARMADA_APISERVER_VERSION: ${{ matrix.kubeapiserver-version }}
     steps: