Update educe dependency
Permit use of educe 0.5.x. No code changes are necessary.
There was a problem with educe 0.5.0 to 0.5.10 inclusive, see educe ticket #14 and MR #15. That's fixed now. Unfortunately we can't express in cargo ">=0.4.6 or >=0.5.11".
Fixes #31 (closed).