Add serverless OpenAPI spec, update README

Author: swallez

openapi-converter/clients_schema_to_openapi/README.md

@@ -8,12 +8,19 @@ The conversion pipeline is the following:
 flowchart LR
     ts[TypeScript API]
     schema[schema.json]
-    openapi[OpenAPI]
+    schema-no-generics[schema-no-generics.json]
+    openapi[openapi.json]
     
     ts --> schema
-    schema --> openapi
+    schema --> schema-no-generics
+    schema-no-generics --> openapi
+    schema-no-generics --> serverless-openapi.json
 ```
 
-This is still a work in progress and this branch is the work for [PR #2047](https://github.com/elastic/elasticsearch-specification/pull/2047) where reviews and comments should be made.
+This branch is the work for [PR #2047](https://github.com/elastic/elasticsearch-specification/pull/2047) where reviews and comments should be made.
 
 The OpenAPI specification generated from the current `schema.json` can be found in the [output/openapi](../../output/openapi) directory.
+
+The generated OpenAPI schemas validate successfully using the rather strict [Spectral OpenAPI linter](https://github.com/stoplightio/spectral), except for endpoint (this is an ES API issue). You can run the linter using:
+* `npm run validate` for the Stack/Stateful OpenAPI spec
+* `npm run validate-serverless` for the Serverless OpenAPI spec

openapi-converter/clients_schema_to_openapi/package.json

@@ -5,7 +5,8 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "validate": "./node_modules/.bin/spectral lint ../../output/openapi/elasticsearch-openapi.json"
+    "validate": "./node_modules/.bin/spectral lint ../../output/openapi/elasticsearch-openapi.json",
+    "validate-serverless": "./node_modules/.bin/spectral lint ../../output/openapi/elasticsearch-serverless-openapi.json"
   },
   "author": "",
   "license": "ISC",