Added configuration example to changeset

Author: nathan-ahn

.changeset/spicy-starfishes-press.md

@@ -4,3 +4,27 @@
 ---
 
 Added configuration to allow for custom hash functions for persisted documents in the client preset
+
+### Example
+```ts filename="codegen.ts" {10-12}
+import { type CodegenConfig } from '@graphql-codegen/cli'
+
+const config: CodegenConfig = {
+  schema: 'schema.graphql',
+  documents: ['src/**/*.tsx'],
+  generates: {
+    './src/gql/': {
+      preset: 'client',
+      presetConfig: {
+        persistedDocuments: {
+          hashAlgorithm: operation => {
+            const shasum = crypto.createHash('sha512')
+            shasum.update(operation)
+            return shasum.digest('hex')
+          }
+        }
+      }
+    }
+  }
+}
+```