Bump remove_dir_all

While this fixes a TOCTOU bug in the dependency, rustup is run either as
an unprivileged process, or as a privileged process operating on a file
tree that the privileged user owns; it is not a setuid binary and
that mitigates much of the vulnerability: a deliberately misconfigured
sudoers or similar would be required. Thus this hardens rustup against
misconfiguration, but does not close an active vulnerability in how
rustup is designed to be used.

Author: rbtcollins

Cargo.lock

@@ -47,7 +47,7 @@ openssl = {version = "0.10", optional = true}
 pulldown-cmark = {version = "0.9", default-features = false}
 rand = "0.8"
 regex = "1"
-remove_dir_all = "0.7.0"
+remove_dir_all = {version= "0.8.1", features=["parallel"]}
 same-file = "1"
 scopeguard = "1"
 semver = "1.0"