Fix yarn update

.devcontainer/Dockerfile

@@ -13,8 +13,12 @@ RUN apt-get update \
 # Verify git and process tools are installed
 RUN apt-get install -y git procps
 
-# Install yarn 
-RUN apt-get install -y curl apt-transport-https lsb-release \
+# Remove outdated yarn from /opt and install via package 
+# so it can be easily updated via apt-get upgrade yarn
+RUN rm -rf /opt/yarn-* \
+    rm -f /usr/local/bin/yarn \
+    rm -f /usr/local/bin/yarnpkg \
+    && apt-get install -y curl apt-transport-https lsb-release \
     && curl -sS https://dl.yarnpkg.com/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/pubkey.gpg | apt-key add - 2>/dev/null \
     && echo "deb https://dl.yarnpkg.com/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/ stable main" | tee /etc/apt/sources.list.d/yarn.list \
     && apt-get update \
@@ -27,3 +31,4 @@ RUN npm install -g eslint
 RUN apt-get autoremove -y \
     && apt-get clean -y \
     && rm -rf /var/lib/apt/lists/*
+ENV DEBIAN_FRONTEND=dialog