Dockerfile.ubi: get rid of --link flags for COPY operations

not supported by openshift CI (buildah)

See containers/buildah#4325

Dockerfile.ubi

@@ -43,7 +43,7 @@ RUN curl -fsSL -o ~/miniforge3.sh -O  "https://github.com/conda-forge/miniforge/
 ## Python Base #################################################################
 FROM base as python-base
 
-COPY --from=python-install --link /opt/vllm /opt/vllm
+COPY --from=python-install /opt/vllm /opt/vllm
 
 ENV PATH=/opt/vllm/bin/:$PATH
 
@@ -132,7 +132,7 @@ RUN ldconfig /usr/local/cuda-12.2/compat/
 ## Development #################################################################
 FROM cuda-devel AS dev
 
-COPY --from=python-torch-base --link /opt/vllm /opt/vllm
+COPY --from=python-torch-base /opt/vllm /opt/vllm
 ENV PATH=/opt/vllm/bin/:$PATH
 
 # install build and runtime dependencies
@@ -260,9 +260,9 @@ FROM base AS vllm
 
 WORKDIR /vllm-staging
 # COPY files from various places into a staging directory
-COPY --link vllm vllm
-COPY --from=build --link /workspace/vllm/*.so vllm/
-COPY --from=gen-protos --link /workspace/vllm/entrypoints/grpc/pb vllm/entrypoints/grpc/pb
+COPY vllm vllm
+COPY --from=build /workspace/vllm/*.so vllm/
+COPY --from=gen-protos /workspace/vllm/entrypoints/grpc/pb vllm/entrypoints/grpc/pb
 
 # custom COPY command to use umask to control permissions and grant permissions
 # to the group
@@ -281,7 +281,7 @@ FROM cuda-runtime AS vllm-openai
 WORKDIR /workspace
 
 # Create release python environment
-COPY --from=python-torch-base --link /opt/vllm /opt/vllm
+COPY --from=python-torch-base /opt/vllm /opt/vllm
 ENV PATH=/opt/vllm/bin/:$PATH
 
 RUN --mount=type=cache,target=/root/.cache/pip \
@@ -301,7 +301,7 @@ RUN --mount=type=bind,from=flash-attn-builder,src=/usr/src/flash-attention-v2,ta
     pip3 install /usr/src/flash-attention-v2/*.whl --no-cache-dir
 
 # vLLM will not be installed in site-packages
-COPY --from=vllm --link /workspace/ ./
+COPY --from=vllm /workspace/ ./
 
 # Triton needs a CC compiler
 RUN microdnf install -y gcc \