The CacheFolder properties should actually be nullabe

Author: Piedone

Diff for: src/ImageSharp.Web.Providers.AWS/Caching/AWSS3StorageCacheOptions.cs

@@ -17,7 +17,7 @@ public class AWSS3StorageCacheOptions : IAWSS3BucketClientOptions
     /// <summary>
     /// Gets or sets the cache folder's name that'll store cache files under the configured bucket.
     /// </summary>
-    public string CacheFolder { get; set; } = null!;
+    public string? CacheFolder { get; set; }
 
     /// <inheritdoc/>
     public string? AccessKey { get; set; }

Diff for: src/ImageSharp.Web.Providers.Azure/Caching/AzureBlobStorageCacheOptions.cs

@@ -26,5 +26,5 @@ public class AzureBlobStorageCacheOptions
     /// Must conform to Azure Blob Storage directory naming guidelines.
     /// <see href="https://learn.microsoft.com/en-us/rest/api/storageservices/naming-and-referencing-containers--blobs--and-metadata#directory-names"/>
     /// </summary>
-    public string CacheFolder { get; set; } = null!;
+    public string? CacheFolder { get; set; }
 }