Update README.md (#172)

* Update README.md

* Create nice-turkeys-count.md

Author: natemoo-re

.changeset/nice-turkeys-count.md

@@ -0,0 +1,5 @@
+---
+"astro-icon": patch
+---
+
+Fix broken link in README

packages/core/README.md

@@ -230,7 +230,7 @@ export default defineConfig({
 
 ## Migrating to v1
 
-`astro-icon` v1 contains a number of breaking changes. Please reference the [**Migrate to `astro-icon` v1** guide](https://github.com/natemoo-re/astro-icon/tree/main/docs/migrate-to-v1.md) to update from older versions of `astro-icon`.
+`astro-icon` v1 contains a number of breaking changes. Please reference the [**Migrate to `astro-icon` v1** guide](https://www.astroicon.dev/guides/upgrade/v1/) to update from older versions of `astro-icon`.
 
 ## Contributing