Remove unneeded setup step from CI instructions in readme

Author: dtolnay

README.md

@@ -127,16 +127,11 @@ MIRI_NIGHTLY=nightly-$(curl -s https://rust-lang.github.io/rustup-components-his
 echo "Installing latest nightly with Miri: $MIRI_NIGHTLY"
 rustup set profile minimal
 rustup default "$MIRI_NIGHTLY"
-
 rustup component add miri
-cargo miri setup
 
 cargo miri test
 ```
 
-We use `cargo miri setup` to avoid getting interactive questions about the extra
-setup needed for Miri.
-
 ### Common Problems
 
 When using the above instructions, you may encounter a number of confusing compiler