Fix build docs
* Update rust version requirement in doc/build.md
* Apply previous updates to doc/build_ES.md
English version was updated and ES version wasn't kept in sync
@@ -12,7 +12,7 @@ What's working so far?
## Requirements
-* rust 1.26+ (use [rustup]((https://www.rustup.rs/))- i.e. `curl https://sh.rustup.rs -sSf | sh; source $HOME/.cargo/env`)
+* rust 1.30+ (use [rustup]((https://www.rustup.rs/))- i.e. `curl https://sh.rustup.rs -sSf | sh; source $HOME/.cargo/env`)
* if rust is already installed, you can simply update version with `rustup update`
* clang
* ncurses and libs (ncurses, ncursesw5)
