chore(deps): update dependency json-schema-to-typescript to v15 (#647)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -36,7 +36,7 @@
     "@types/node": ">= 8",
     "github-openapi-graphql-query": "^4.0.0",
     "handlebars": "^4.7.6",
-    "json-schema-to-typescript": "^14.0.0",
+    "json-schema-to-typescript": "^15.0.0",
     "lodash.set": "^4.3.2",
     "npm-run-all2": "^6.0.0",
     "pascal-case": "^4.0.0",