fix syntax (#821)

Author: nv-alaiacano

docker/dockerfile.merlin

@@ -305,7 +305,7 @@ RUN git clone --branch ${MODELS_VER} --depth 1 https://github.com/NVIDIA-Merlin/
     cd /models/ && pip install . --no-deps
 
 # Install Transformers4Rec
-RUN git clone --branch ${TF4REC_VER}} --depth 1 https://github.com/NVIDIA-Merlin/Transformers4Rec.git /transformers4rec && \
+RUN git clone --branch ${TF4REC_VER} --depth 1 https://github.com/NVIDIA-Merlin/Transformers4Rec.git /transformers4rec && \
     cd /transformers4rec/ && pip install . --no-deps
 
 HEALTHCHECK NONE