Create a Node-API release checklist

[gabrielschulhof]

What is the problem this feature will solve?

We need to make sure when we release a new version of Node-API we do not overlook any of the steps.

What is the feature you are proposing to solve the problem?

Let's add a document to the guides containing a list of steps necessary for creating a Node-API release PR.

What alternatives have you considered?

Looking at existing release commits to remember the steps. However, a new step will be added at https://github.com/nodejs/node/pull/45715/files#diff-2057dbe503dbb37a65a74cf86e056d50c27ba828070577e0f7f07e734365c9bcR658 which previous releases will not reflect.

[gabrielschulhof]

With #45715 landed, the document must also mention that, as part of the release process, not only will new APIs in the headers have to be moved from NAPI_EXPERIMENTAL sections to NAPI_VERSION >= n sections, but, in the implementation files (node_api.cc and js_native_api_v8.cc), checks of the form if (env->module_api_version != NAPI_EXPERIMENTAL) have to be replaced with checks of the form if (env->module_api_version <= n).