Update migration and readme

Author: timfish

docs/migration/v8-to-v9.md

@@ -260,15 +260,17 @@ Let us know if this is causing issues in your setup by opening an issue on GitHu
 
 ### `@sentry/deno`
 
-- The import of Sentry from the deno registry has changed. Use the `import * as Sentry from 'https://deno.land/x/sentry/build/index.mjs'` import instead.
+- `@sentry/deno` is no longer published on `deno.land` so you'll need to import
+  from npm:
 
-  ```js
-  // before
-  import * as Sentry from 'https://deno.land/x/sentry/index.mjs';
+```javascript
+import * as Sentry from 'npm:@sentry/deno';
 
-  // after
-  import * as Sentry from 'https://deno.land/x/sentry/build/index.mjs';
-  ```
+Sentry.init({
+  dsn: '__DSN__',
+  // ...
+});
+```
 
 ## 6. Type Changes
 

packages/deno/README.md

@@ -25,10 +25,6 @@ To use this SDK, call `Sentry.init(options)` as early as possible in the main en
 and hook into the environment. Note that you can turn off almost all side effects using the respective options.
 
 ```javascript
-// Import from the Deno registry
-import * as Sentry from 'https://deno.land/x/sentry/build/index.mjs';
-
-// or import from npm registry
 import * as Sentry from 'npm:@sentry/deno';
 
 Sentry.init({