Update packages/attest/README.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

README.md

@@ -236,7 +236,7 @@ export type PackageRegistryOptions = {
 token: string
 // Optional parameters for the write operation.
 // The number of times to retry the request.
-cusomtRetry?: number
+customRetry?: number
 // HTTP headers to include in request to Artifact Metadata API.
 headers?: RequestHeaders
 ```