fix: pin mmcv>=2.0.0rc4,<2.2.0

Dockerfile

@@ -24,7 +24,7 @@ RUN pip install --no-cache-dir \
 # 2. MMDet 3.x stack: mmengine + mmcv 2.x + mmdet from local submodule
 RUN pip install --no-cache-dir openmim && \
     mim install "mmengine>=0.7.1,<1.0.0" && \
-    mim install "mmcv>=2.0.0,<2.3.0"
+    mim install "mmcv>=2.0.0rc4,<2.2.0"
 
 # 3. Install mmdetection from the local submodule
 RUN pip install --no-cache-dir -v -e ./mmdetection