Use jdk 17 in CI testnet build

Author: dpad85

…ithub/workflows/legacy-testnet-build.yml .github/workflows/testnet-build.yml.github/workflows/legacy-testnet-build.yml renamed to .github/workflows/testnet-build.yml .github/workflows/legacy-testnet-build.yml renamed to .github/workflows/testnet-build.yml

@@ -58,10 +58,10 @@ jobs:
         key: ${{ runner.os }}-konan-${{ hashFiles('**/*.gradle*') }}-${{ hashFiles('**/gradle/wrapper/gradle-wrapper.properties') }}
         restore-keys: ${{ runner.os }}-konan-
 
-    - name: Set up jdk 1.11
+    - name: Set up jdk 1.17
       uses: actions/setup-java@v1
       with:
-         java-version: 11
+         java-version: 17
 
     # 3 - build dependencies & app