explicitly update file mode with a+rx for entrypoint.sh, because when building directly from git, it would only set u=rx for it.

alpine/Dockerfile

@@ -33,5 +33,7 @@ WORKDIR /var/ts3server/
 EXPOSE 9987/udp 10011 30033 
 
 COPY entrypoint.sh /opt/ts3server
+RUN chmod a+rx /opt/ts3server/entrypoint.sh
+
 ENTRYPOINT [ "entrypoint.sh" ]
 CMD [ "ts3server" ]