Fix Docker build wrapper line endings

Author: BeomSeokYu

Dockerfile

@@ -8,6 +8,7 @@ COPY gradle gradle
 COPY build.gradle settings.gradle ./
 COPY src src
 
+RUN sed -i 's/\r$//' gradlew
 RUN chmod +x gradlew
 RUN ./gradlew --no-daemon clean bootJar -x test