Rename title from 'Workers API' to 'Workflows API'

Just noticed this and was confused by the title of this page. Feel free to close if this is intentional.

Author: emily-shen

src/content/docs/workflows/build/workers-api.mdx

@@ -1,5 +1,5 @@
 ---
-title: Workers API
+title: Workflows API
 pcx_content_type: concept
 sidebar:
   order: 2