Use Yarn 2 for Docker builds to avoid network timeout issues.

Dockerfile

@@ -27,6 +27,7 @@ RUN apk add --no-cache \
     make \
     nasm \
     nodejs \
+    npm \
     yarn \
     zlib-dev
 
@@ -45,6 +46,7 @@ WORKDIR /pgadmin4/web
 
 # Build the JS vendor code in the app-builder, and then remove the vendor source.
 RUN export CPPFLAGS="-DPNG_ARM_NEON_OPT=0" && \
+    yarn set version berry && \
     yarn install && \
     yarn run bundle && \
     rm -rf node_modules \