[Build][Ray] Fix protobuf version in Dockerfile (#2028)

### What this PR does / why we need it?
Fix protobuf version in Dockerfile to resolve `AttributeError: 'str'
object has no attribute 'DESCRIPTOR' when packaging message to dict`
using protobuf. will remove version specification after
https://github.com/ray-project/ray/pull/54910 is merged

### Does this PR introduce _any_ user-facing change?
N/A

### How was this patch tested?
CI passed with existing test.

- vLLM version: v0.10.0
- vLLM main:
0e36abf993

Signed-off-by: MengqingCao <cmq0113@163.com>

Dockerfile.a3

@@ -54,7 +54,7 @@ RUN export PIP_EXTRA_INDEX_URL=https://mirrors.huaweicloud.com/ascend/repos/pypi
     python3 -m pip cache purge
 
 # Install modelscope (for fast download) and ray (for multinode)
-RUN python3 -m pip install modelscope ray && \
+RUN python3 -m pip install modelscope 'ray>=2.47.1' 'protobuf>3.20.0' && \
     python3 -m pip cache purge
 
 CMD ["/bin/bash"]