Convert Strings to SecretStrings

[gakonst]

As title. Also in a few places where we use String in Warp, they can be automatically converted via Secrecy's FromStr implementation, after a new release is made.

Originally posted by @gakonst in #553

[emschwartz]

Is this still blocked?

[gakonst]

Yeah, so the Secrecy version which includes that is 0.6 which updated bytes to 0.5 which itself had a few breaking changes. I am not sure yet how much effort is required, but would probably mean the whole repo needs to move to bytes 0.5. @tarcieri do you think it'd be possible to make a minor Secrecy release as 0.5.2, with iqlusioninc/crates#309 in it? Currently evaluating how much effort might be required to upgrade to bytes

[tarcieri]

Yeah, I can do that.

Also in a pinch you can include two different versions of bytes (I had to do that in the tendermint crate because Prost hasn't updated yet), but avoiding that is probably for the best.

[tarcieri]

Made a backport PR here: iqlusioninc/crates#316

[tarcieri]

It's out: https://crates.io/crates/secrecy/0.5.2