spring is marked for autoremoval from testing

[Debian testing autoremoval watch]

spring 104.0+dfsg-4 is marked for autoremoval from testing on 2020-03-23

It is affected by these RC bugs:
951974: spring: FTBFS: ./obj-x86_64-linux-gnu/CMakeFiles/CMakeTmp/./obj-x86_64-linux-gnu/CMakeFiles/CMakeTmp/src.c:11: undefined reference to `pthread_create'