Add rustc-dev component

Author: JohnTitor

ci/semver.sh

@@ -13,6 +13,8 @@ if ! rustc --version | grep -E "nightly" ; then
     exit 1
 fi
 
+rustup component add rustc-dev
+
 # FIXME: Use upstream once it gets rustup.
 cargo +nightly install semververfork