build: configure UTF-8 locale in devcontainer (openai#774)

Author: stainless-bot

.devcontainer/Dockerfile

@@ -7,6 +7,10 @@ RUN apt-get update && apt-get install -y \
   yarnpkg \
   && apt-get clean autoclean
 
+# Ensure UTF-8 encoding
+ENV LANG=C.UTF-8
+ENV LC_ALL=C.UTF-8
+
 # Yarn
 RUN ln -sf /usr/bin/yarnpkg /usr/bin/yarn