refactor(fix): Flatten workspace loading

This misses out on features that shouldn't be relevant to fix, like
avoid-dev-deps.

However, this prepares the way for workspace re-loading.

Author: epage

src/bin/cargo/commands/fix.rs

@@ -1,5 +1,6 @@
 use crate::command_prelude::*;
 
+use cargo::core::Workspace;
 use cargo::ops;
 
 pub fn cli() -> Command {
@@ -69,7 +70,8 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
 
     // Unlike other commands default `cargo fix` to all targets to fix as much
     // code as we can.
-    let ws = args.workspace(gctx)?;
+    let root_manifest = args.root_manifest(gctx)?;
+    let ws = Workspace::new(&root_manifest, gctx)?;
     let mut opts = args.compile_options(gctx, mode, Some(&ws), ProfileChecking::LegacyTestOnly)?;
 
     if !opts.filter.is_specific() {