Bump NVM script version to 0.33.1 (#658)

https://github.com/creationix/nvm/releases/tag/v0.33.1

workspace/Dockerfile

@@ -195,7 +195,7 @@ ENV INSTALL_NODE ${INSTALL_NODE}
 ENV NVM_DIR /home/laradock/.nvm
 RUN if [ ${INSTALL_NODE} = true ]; then \
     # Install nvm (A Node Version Manager)
-    curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.6/install.sh | bash && \
+    curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.1/install.sh | bash && \
         . $NVM_DIR/nvm.sh && \
         nvm install ${NODE_VERSION} && \
         nvm use ${NODE_VERSION} && \