Set body parser limit size

[mtb-xt]

Hello.

We've been getting an error in the plugin:

PayloadTooLargeError: request entity too large
   at readStream (/app/node_modules/raw-body/index.js:155:17)
   at getRawBody (/app/node_modules/raw-body/index.js:108:12)
   at read (/app/node_modules/body-parser/lib/read.js:77:3)
   at jsonParser (/app/node_modules/body-parser/lib/types/json.js:135:5)
   at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
   at next (/app/node_modules/express/lib/router/route.js:137:13)
   at Route.dispatch (/app/node_modules/express/lib/router/route.js:112:3)
   at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
   at /app/node_modules/express/lib/router/index.js:281:22
   at Function.process_params (/app/node_modules/express/lib/router/index.js:335:12)

This simple change fixed the issue for us. Could we merge this, please?

[microadam]

Thanks for the fix!