chore: Switch from yarn to pnpm

Dockerfile

@@ -3,14 +3,14 @@ FROM docker.io/library/node:20-alpine3.18 AS mermaid-live-editor-dependencies
 RUN apk --no-cache add build-base git python3 && \
     rm -rf /var/cache/apk/*
 
-RUN yarn global add node-gyp
+RUN npm install -g pnpm
 
 WORKDIR /app
 
 COPY ./package.json .
-COPY ./yarn.lock .
+COPY ./pnpm-lock.yaml .
 
-RUN yarn install
+RUN pnpm install
 
 FROM mermaid-live-editor-dependencies AS mermaid-live-editor-builder
 
@@ -22,11 +22,11 @@ ARG MERMAID_IS_ENABLED_MERMAID_CHART_LINKS
 
 COPY . ./
 
-RUN yarn build
+RUN pnpm build
 
 FROM mermaid-live-editor-builder AS mermaid-dev
 
-ENTRYPOINT ["yarn", "dev"]
+ENTRYPOINT ["pnpm", "dev"]
 
 FROM nginx:1.25-alpine3.18 AS mermaid