Use junctions for directory links on Windows

Using symlinks on Windows requires that our users enable Developer
mode, which isn't always possible. For directory links, there is an
easy solution: NTFS Junctions. These work the same as symlinks but
do not require administrator privileges nor developer mode.

Author: charlespierce

Cargo.lock

@@ -55,3 +55,4 @@ fs2 = "0.4.3"
 
 [target.'cfg(windows)'.dependencies]
 winreg = "0.52.0"
+junction = "1.1.0"

crates/volta-core/Cargo.toml

@@ -138,7 +138,7 @@ where
     D: AsRef<Path>,
 {
     #[cfg(windows)]
-    return std::os::windows::fs::symlink_dir(src, dest);
+    return junction::create(src, dest);
 
     #[cfg(unix)]
     return std::os::unix::fs::symlink(src, dest);