bst-external is marked for autoremoval from testing

[Debian testing autoremoval watch]

bst-external 0.18.0-1 is marked for autoremoval from testing on 2020-08-07

It is affected by these RC bugs:
941714: bst-external: please make the build reproducible

It (build-)depends on packages with these RC bugs:
959675: libgrpc++1: libgrpc++1: endless looping with default settings
961193: libgrpc++1: libgrpc++1 must be linked with libatomic on armel/mips/mipsel/powerpc
963583: libgrpc++1: libgrpc++1 changes ABI without changing soname