docs: update readme

Author: dphang

README.md

@@ -535,6 +535,7 @@ The fourth cache behaviour handles next API requests `api/*`.
 | build.postBuildCommands | `Array` | `[]` | Any commands to run post-build and pre-deploy. For example, you can run any custom code on the `.serverless_nextjs` directory e.g you can copy additional files into the Lambda: see https://github.com/serverless-nextjs/serverless-next.js/issues/767#issuecomment-722967719 for an example for `next-18n`. Only applies during execution of the `serverless` command. |
 | build.cleanupDotNext | `boolean` | `true` | Whether to clean up `.next` directory before running the build step |
 | build.assetIgnorePatterns | `string[]` | `[]` | Glob patterns to ignore when discovering files to copy from _next/static, public, static directories. |
+| build.separateApiLambda | `boolean` | `true` | **Experimental** Set this to false to serve API routes from the default handler. Settinng to false also allows rewrites between API routes and normal page routes. Note: this is marked experimental and not fully tested, use with caution. Please report any bugs by opening an issue.
 | cloudfront | `object` | `{}` | Inputs to be passed to [aws-cloudfront](https://github.com/serverless-components/aws-cloudfront) |
 | certificateArn | `string` | `` | Specific certificate ARN to use for CloudFront distribution. Helpful if you have a wildcard SSL cert you wish to use. This currently works only in tandem with the`domain`input. Please check [custom CloudFront configuration](https://github.com/serverless-nextjs/serverless-next.js#custom-cloudfront-configuration) for how to specify`certificate`without needing to use the`domain`input (note that doing so will override any certificate due to the domain input). | | domainType |`string` |`"both"` | Can be one of:`"apex"`- apex domain only, don't create a www subdomain.`"www"` - www domain only, don't create an apex subdomain.`"both"`- create both www and apex domains when either one is provided. | | publicDirectoryCache |`boolean\|object`|`true` | Customize the`public`/`static`folder asset caching policy. Assigning an object with`value`and/or`test`lets you customize the caching policy and the types of files being cached. Assigning false disables caching | | useServerlessTraceTarget |`boolean` |`false` | Use the experimental-serverless-trace target to build your next app. This is the same build target that Vercel Now uses. See this [RFC](https://github.com/vercel/next.js/pull/8246) for details. Note: while using this, you may need to set`NODE*ENV`variable to`production`. | | logLambdaExecutionTimes | `boolean` |`false` | Logs to CloudWatch the default handler performance metrics. | | minifyHandlers |`boolean` |`false` | Use pre-built minified handlers to reduce code size. Does not minify custom handlers. | | deploy |`boolean` |`true` | Whether to deploy resources to AWS (available in the latest alpha). Useful if you just need the build outputs (Lambdas and assets) but want to deploy them yourself. Build outputs will be created in the`.serverless_nextjs`directory. You are then responsible to configure AWS yourself: setting CloudFront behaviors with Lambda function associations, uploading assets to S3 with the proper`Cache-Control`headers, etc. | | enableHTTPCompression |`boolean` |`false` | When set to`true`the Lambda@Edge functions for SSR and API requests will use Gzip to compress the response. Note that you shouldn't need to enable this because CloudFront will compress responses for you out of the box. | | authentication |`object` |`undefined` | Authentication object for use with basic authentication (available from 1.19.0-alpha.3). It only supports a single username/password combination for now and is inlined in plaintext in the Lambda handler. You must also forward the`Authorization`header for CloudFront behaviors, e.g`defaults`, `api/*`, and `\_next/data/\_`. **Note: this is meant as a simple means of protecting an environment such as a development/test site, it is not recommended for production use.** | | authentication.username | `string` |`undefined` | Username for basic authentication. | | authentication.password |`string` |`undefined` | Password for basic authentication. **Note: it is highly recommended not to reuse a password here as it gets inlined in plaintext in the Lambda handler.** | | enableS3Acceleration |`boolean` |`true` | Whether to enable S3 transfer acceleration. This may be useful to disable as some AWS regions do not support it. See [reference](https://docs.amazonaws.cn/en_us/aws/latest/userguide/s3.html). |