Tweak regex

Author: graydon

install-rust.sh

@@ -17,7 +17,7 @@ set -x
 # version) that we want to install. This value will change relatively often, as
 # new Rust _compilers_ are released, but you should only have to change it in
 # rust-toolchain.toml. This file will pick it up automatically.
-RUST_VERSION=$(perl -ne 'if (/channel\s+=\s+"(\d+\.\d+.?\d+)"/) { print $1 }' rust-toolchain.toml)
+RUST_VERSION=$(perl -ne 'if (/channel\s+=\s+"(\d+(?:\.\d+)+)"/) { print $1 }' rust-toolchain.toml)
 
 if [[ -z "$RUST_VERSION" ]]; then
     echo "RUST_VERSION is empty"