Fix environment variables

Dockerfile

@@ -2,3 +2,9 @@ FROM ruby:alpine
 RUN apk add --update build-base libffi-dev ruby-dev
 RUN gem install ffi
 RUN gem install fastlane -NV
+
+# Set environment variables for fastlane
+ENV LC_ALL=en_US.UTF-8
+ENV LANG=en_US.UTF-8
+
+ENTRYPOINT ["fastlane"]