[Java] Use bionic repos for Clang installation

Author: vyazelenko

.github/workflows/ci.yml

@@ -128,7 +128,7 @@ jobs:
  key: ${{ runner.os }}-gradle-wrapper
  - name: Install compiler
  run: |
- sudo add-apt-repository "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-${{ matrix.version }} main"
+ sudo add-apt-repository "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-${{ matrix.version }} main"
 
  sudo apt-get update