fix: update Dockerfile to copy both package.json and yarn.lock for installation

Author: Siddhant-K-code

.devcontainer/Dockerfile

@@ -16,7 +16,7 @@ RUN ln -sf /usr/bin/yarnpkg /usr/bin/yarn
 
 WORKDIR /workspace
 
-COPY package.json /workspace/
+COPY package.json yarn.lock /workspace/
 
 RUN yarn install