Update gradle.yml Java 21

Author: tanishisherewithhh

.github/workflows/gradle.yml

@@ -41,7 +41,7 @@ jobs:
         run: rm ./build/libs/*-sources.jar || true
 
       - name: capture build artifacts
-        if: ${{ runner.os == 'Linux' && matrix.java == '17' }} # Only upload artifacts built from the latest java on one OS
+        if: ${{ runner.os == 'Linux' && matrix.java == '21' }} # Only upload artifacts built from the latest java on one OS
         uses: actions/upload-artifact@v3
         with:
           name: Dynamichud