TEST: use gcc to compile UCX in clang-tidy-rocm

The hip header file generates a warning when compiled with clang, which in itself is harmless, but because all warnings are treated as errors, the compilation fails in the UCX step. Compile UCX with gcc instead of clang (since we are not truly interested in running clang-tidy on ucx in this CI, but just on UCC)

.github/workflows/clang-tidy-rocm.yaml

@@ -31,7 +31,7 @@ jobs:
     - name: Build UCX
       run: |
         cd /tmp/ucx && ./autogen.sh
-        CC=clang-${CLANG_VER} CXX=clang++-${CLANG_VER} ./contrib/configure-release --without-java --without-go --disable-numa --prefix $PWD/install --with-rocm=/opt/rocm
+        CC=gcc CXX=g++ ./contrib/configure-release --without-java --without-go --disable-numa --prefix $PWD/install --with-rocm=/opt/rocm
         make -j install
     - uses: actions/checkout@v1
     - name: Build UCC