Fix build: "sh: 1: node: Permission denied" (#199)

* add `--unsafe-perm` flag

* remove . so that .nvmrc file is used

Author: jhuleatt

Dockerfile

@@ -10,8 +10,8 @@ RUN DEBIAN_FRONTEND=noninteractive apt-get install -qq curl default-jre < /dev/n
 
 RUN curl --silent -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.0/install.sh | bash
 COPY .nvmrc /
-RUN nvm install .
-RUN npm install -g yarn firebase-tools
+RUN nvm install
+RUN npm install --unsafe-perm -g yarn firebase-tools
 RUN firebase setup:emulators:firestore
 
 ENV PYTHON /usr/bin/python2.7