Remove needless dependencies

[eregon]

These are default gems, so there is no need to explicitly depend on them,
and depending on them is actually harmful: https://bugs.ruby-lang.org/issues/18567.

[hsbt]

same as ruby/net-imap#56 (comment)

[hsbt]

I will revert this change when we remove digest or/and timeout from the Ruby stdlibs.

[eregon]

I will revert this change when we remove digest or/and timeout from the Ruby stdlibs.

Is there any plan to do so? That sounds extremely disruptive and never worth it.
digest/timeout are used by so many Ruby programs, and they all assume it's part of stdlib.

[hsbt]

digest/timeout are used by so many Ruby programs, and they all assume it's part of stdlib.

Yes, Because I added them to dependencies. But You refuse it. I have no idea to care it.

[eregon]

Right, but thousands of Ruby devs would need to add the dependency, not just in a few default gems.
Anyway, I was just curious if there was already a discussion on Redmine (or a plan documented somewhere) to remove digest/timeout from stdlib and what is the rationale. I suspect the gain/cost is very low.