fix dockerfile of the raspberry_pi code

thing/raspberry_pi/Dockerfile

@@ -19,7 +19,7 @@ RUN git clone https://github.com/Seeed-Studio/grove.py && \
     pip3 install .
 
 # copy sensor files
-COPY .. .
+COPY . .
 
 # install dependencies, build and run the application
 RUN npm install && \