change dockerfile to trigger codespace build

.devcontainer/Dockerfile

@@ -3,6 +3,7 @@ FROM mcr.microsoft.com/devcontainers/anaconda:0-3
 # Copy environment.yml (if found) to a temp location so we update the environment. Also
 # copy "noop.txt" so the COPY instruction does not fail if no environment.yml exists.
 COPY environment.yml* .devcontainer/noop.txt /tmp/conda-tmp/
+
 RUN if [ -f "/tmp/conda-tmp/environment.yml" ]; then umask 0002 && /opt/conda/bin/conda env update -n base -f /tmp/conda-tmp/environment.yml; fi \
     && rm -rf /tmp/conda-tmp