Update cargo to 2024 edition (#842)

Some effects of this change:
- New formatting changes across many files. No functionality changes
should occur from that.
- Calls to `set_env` are considered unsafe, since this only happens in
tests we wrap them in `unsafe` blocks

codex-rs/execpolicy/src/policy_parser.rs

@@ -1,10 +1,10 @@
 #![allow(clippy::needless_lifetimes)]
 
-use crate::arg_matcher::ArgMatcher;
-use crate::opt::OptMeta;
 use crate::Opt;
 use crate::Policy;
 use crate::ProgramSpec;
+use crate::arg_matcher::ArgMatcher;
+use crate::opt::OptMeta;
 use log::info;
 use multimap::MultiMap;
 use regex::Regex;
@@ -15,9 +15,9 @@ use starlark::environment::Module;
 use starlark::eval::Evaluator;
 use starlark::syntax::AstModule;
 use starlark::syntax::Dialect;
+use starlark::values::Heap;
 use starlark::values::list::UnpackList;
 use starlark::values::none::NoneType;
-use starlark::values::Heap;
 use std::cell::RefCell;
 use std::collections::HashMap;