Update Dependabot and CI configuration

Signed-off-by: Patryk Miś <[email protected]>

Author: PatrykMis

.github/dependabot.yml

@@ -4,9 +4,9 @@ updates:
     directory: "/"
     schedule:
       interval: daily
-    target-branch: main
+    target-branch: "15.1"
   - package-ecosystem: gradle
     directory: "/"
     schedule:
       interval: daily
-    target-branch: main
+    target-branch: "15.1"

.github/workflows/build.yml

@@ -8,11 +8,11 @@ jobs:
 
     steps:
       - uses: actions/checkout@v5
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
-          java-version: 21
+          java-version: 25
           cache: gradle
       - name: Build with Gradle
         run: ./gradlew build --no-daemon