fix: NullReferenceException in RemoveLoading (#39) + bump to 7.0.3

[IvanMurzak]

Summary

Fixes the NullReferenceException reported in #39 and bumps the package to 7.0.3.

Root cause

In Future.Loading.List.cs, RemoveLoading(string url) calls loadingInProcess.TryRemove(url, out var future). When TryRemove returns false (the entry is not present — e.g. it was already removed by a concurrent completion/cancellation), the out variable future is null. The else (warning) branch then logged Future[id={future.Id}], dereferencing the null future and throwing NullReferenceException.

Fix

In the warning branch, log using the in-scope url only, without dereferencing the null future:

- Debug.LogWarning($"[ImageLoader] Future[id={future.Id}] Wasn't able to remove loading registration, not found in loading tasks\n{url}");
+ Debug.LogWarning($"[ImageLoader] Wasn't able to remove loading registration, not found in loading tasks\n{url}");

The DebugLevel.Warning guard, indentation, and code style are preserved. The success branch (where future is non-null) is unchanged.

Review outcome

Ran a high-effort code review over the diff. No additional non-minor findings:

• The surrounding lock (loadingInProcess) shared between RegisterLoading/RemoveLoading makes the check-then-act atomic and consistent; locking is sound.
• The only other deref of an out from a failed lookup — anotherLoadingFuture at the RegisterLoading call site — is only used on the path where the value was set by a successful TryGetValue (non-null), so it is safe.
• No other TryRemove/TryGetValue null-deref sites exist in the file or its immediate call sites.

Version bump

Ran bump-version.ps1 -NewVersion 7.0.3, which updated package.json and the Installer.cs Version constant (README was already dropped from the bump targets upstream).

Fixes #39

[IvanMurzak]

Lets still print the future id if it is known, if not lets replace it with "null"

Future[id={future?.Id}]