docs: update TensorRT-LLM commit for multimodal EPD to v1.2.0rc3 (#4713)

Signed-off-by: Dan Gil <dagil@nvidia.com>

docs/backends/trtllm/multimodal_epd.md

@@ -8,7 +8,7 @@ This is an experimental feature that requires using a specific TensorRT-LLM comm
 To enable it build the dynamo container with the `--tensorrtllm-commit` flag, followed by the commit hash:
 
 ```bash
-./container/build.sh --framework trtllm --tensorrtllm-git-url https://github.com/NVIDIA/TensorRT-LLM.git --tensorrtllm-commit v1.2.0rc2
+./container/build.sh --framework trtllm --tensorrtllm-git-url https://github.com/NVIDIA/TensorRT-LLM.git --tensorrtllm-commit v1.2.0rc3
 ```
 
 ## Key Features