fix: CDN option for Unpic (#23)

# Description

Adds the `cdn` prop to help Unpic understand our transformer is
Cloudinary based.

## Issue Ticket Number

Fixes #22 

<!-- Specify above which issue this fixes by referencing the issue
number (`#<ISSUE_NUMBER>`) or issue URL. -->
<!-- Example: Fixes
https://github.com/cloudinary-community/svelte-cloudinary/issues/<ISSUE_NUMBER>
-->

## Type of change

<!-- Please select all options that are applicable. -->

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Fix or improve the documentation
- [ ] This change requires a documentation update


# Checklist

<!-- These must all be followed and checked. -->

- [ ] I have followed the contributing guidelines of this project as
mentioned in [CONTRIBUTING.md](/CONTRIBUTING.md)
- [ ] I have created an
[issue](https://github.com/cloudinary-community/svelte-cloudinary/issues)
ticket for this PR
- [ ] I have checked to ensure there aren't other open [Pull
Requests](https://github.com/cloudinary-community/svelte-cloudinary/pulls)
for the same update/change?
- [ ] I have performed a self-review of my own code
- [ ] I have run tests locally to ensure they all pass
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes needed to the documentation

Author: colbyfayock

svelte-cloudinary/src/lib/components/CldImage.svelte

@@ -71,14 +71,15 @@
 <Image
 	{...$$props}
 	{...imageProps}
+	cdn="cloudinary"
 	transformer={({ width, url, height}) => {
-		return 	getCldImageUrl({
+		return getCldImageUrl({
 			...imageProps,
 			...cldOptions,
 			width,
 			height,
-			src:url
+			// @ts-ignore
+			src: url
 		})}
 	}
-	src={url}
 />