Fails to build on archlinux with serialization-protobuf

[kpcyrd]

archlinux ships protobuf 3.6.0.1, since the crate explicitly requires 3.5.1, the crate fails to build when executing:

cargo check --features=serialization-protobuf

Somewhat related to SpinResearch/RustySecrets#70

[psivesely]

Try running ./install_protobuf.sh in the top-level directory of this repository. For simplicitly and due to limited developer hours, we have decided to limit protobuf support to a single version.

We've had problems with protobuf and/or the complementary Rust crate not following semver correctly, and so have decided to pin a single version instead of allowing any semver-compliant version.

[psivesely]

@kpcyrd Btw good to see you in a totally different repo 😄

[kpcyrd]

@nvesely just thought the same :D I ran into this issue while trying to use RustySecrets and I'm consdering creating a friendly fork that uses the same code base for shamir's secret sharing, but uses a nom parser instead of protobuf. (and also takes care of issues like SpinResearch/RustySecrets#71)

I'm going to make sure everything including the licensing is setup in a way that the code can be upstreamed eventually if there's interest. Would that work for you?