fix: Interpret PermissionDenied as reason to retry on lock acquisition failure. (#386)

Evidence from CI suggests that on windows 'AlreadyExists' isn't the
common error code. Instead, maybe due to racyness, it can also emit
PermissionDenied errors which we now handle specifically.

Author: Byron

git-lock/src/acquire.rs

@@ -121,6 +121,12 @@ fn lock_with_mode<T>(
                 attempts += 1;
                 match try_lock(&lock_path, directory, cleanup.clone()) {
                     Ok(v) => return Ok((lock_path, v)),
+                    #[cfg(windows)]
+                    Err(err) if err.kind() == AlreadyExists || err.kind() == PermissionDenied => {
+                        std::thread::sleep(wait);
+                        continue;
+                    }
+                    #[cfg(not(windows))]
                     Err(err) if err.kind() == AlreadyExists => {
                         std::thread::sleep(wait);
                         continue;