chore: fix .spi.yml schema for Swift Package Index compatibility

Author: vkuttyp

.spi.yml

@@ -2,19 +2,20 @@ version: 1
 swift_versions:
   - 5.10
   - 6.0
+platforms:
+  - macos-spm
+  - ios
+  - tvos
+  - watchos
+  - linux
+  - visionos
+  - android
 builder:
   configs:
-    - documentation_targets:
+    - platform: macos-spm
+      documentation_targets:
         - CosmoSQLCore
         - CosmoMSSQL
         - CosmoPostgres
         - CosmoMySQL
         - CosmoSQLite
-      platforms:
-        - android
-        - ios
-        - macos
-        - linux
-        - tvos
-        - watchos
-        - visionos