pin to pnpm 6 for now (#1147)

.circleci/config.yml

@@ -37,7 +37,7 @@ jobs:
       - run:
           name: Build frontend
           command: |
-            npm i pnpm -g
+            npm i pnpm@6 -g
             cd ui
             pnpm i --frozen-lockfile
             pnpm build

website/homepage/Dockerfile

@@ -11,7 +11,7 @@ WORKDIR /gradio
 COPY ./ui ./ui
 RUN mkdir gradio
 COPY ./gradio/version.txt ./gradio/version.txt
-RUN npm i pnpm -g
+RUN npm i pnpm@6 -g
 WORKDIR /gradio/ui
 ENV NODE_OPTIONS="--max-old-space-size=4096"
 RUN pnpm i