Add miri to the proxy list

Author: oli-obk

src/rustup/lib.rs

@@ -31,6 +31,8 @@ pub static TOOLS: &'static [&'static str] = &[
     "rust-gdb",
     "rls",
     "cargo-clippy",
+    "miri",
+    "cargo-miri",
 ];
 
 // Tools which are commonly installed by Cargo as well as rustup. We take a bit