Update Dockerfile

npm error code MODULE_NOT_FOUND
npm error Cannot find module 'promise-retry'

Dockerfile

@@ -7,10 +7,9 @@ ENV RUN_AT_STARTUP=true
 RUN apk update \
     && apk upgrade --available \
     && apk add curl git tzdata bash \
-    && npm install -g npm@latest \
     && npm install pm2 -g \
     && mkdir $(echo "${WORKDIR}") -p \
-    && cd $WORKDIR \
+    && cd $(echo "${WORKDIR}") \
     && git clone --depth 1 -b $(echo "${GIT_BRANCH}") $(echo "${GIT_REPO}") . \
     && npm install \
     && mkdir /public