Add OpenAPI spec URLs to 12 certified API source connectors (#69784)

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

airbyte-integrations/connectors/source-shopify/metadata.yaml

@@ -177,6 +177,9 @@ data:
     - title: Shopify authentication
       url: https://shopify.dev/docs/apps/auth
       type: authentication_guide
+    - title: Shopify Admin API OpenAPI specification
+      url: https://shopify.dev/docs/api/admin-rest
+      type: openapi_spec
     - title: Shopify rate limits
       url: https://shopify.dev/docs/api/usage/rate-limits
       type: rate_limits