201: create a SSOT doc for Cirrus payloads (#203)

* add draft payload doc

* update CHANGELOG

* minor edits to payload.rst

* edits to payload.rst based on PR review

* edits to payload.rst based on PR review, round 2

* edits to payload.rst based on PR review, round 2

* final edits

Author: ping-e84

CHANGELOG.md

@@ -11,11 +11,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - ([#153]) Adds `upload_item_to_s3` method to the `Task` class to upload a
   STAC Item to S3 using configured upload options.
-- add a doc defining `stactask.Task` features (properties, attributes, and instance
-  methods)
 - ([#183]) Adds Task methods to add file metadata to Item Assets (supported by the STAC
   File Info Extension) - user-facing functions are `add_fileinfo_to_local_assets`
   (multiple Item Assets) and `add_fileinfo_to_local_asset` (single Item Asset).
+- add a doc defining `stactask.Task` features (properties, attributes, and instance
+  methods)
+- ([#201]) Adds a payload doc (single source of truth) and adjusts other
+  references accordingly.
 
 ### Changed
 

docs/source/index.rst

@@ -17,5 +17,6 @@ Contents
 .. toctree::
 
    usage
+   payload
    task
    api