[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>

requirements-dev.txt

@@ -14,6 +14,6 @@ pytest-cov
 regex
 sentence_transformers
 ray>=2.47.1
-protobuf==4.25.6
+protobuf>3.20.0
 librosa 
 soundfile