[DOC] changed references from Authors.rst -> Authors.md (pyjanitor-devs#1075)

Author: bill-tucker-zywave

.github/ISSUE_TEMPLATE/documentation_fix.md

@@ -20,4 +20,4 @@ I would like to propose a change, such that now the docs...
 to get you started. -->
 
 - [Link to documentation page](https://pyjanitor-devs.github.io/pyjanitor/)
-- [Link to exact file to be edited](https://github.com/pyjanitor-devs/pyjanitor/blob/dev/AUTHORS.rst)
+- [Link to exact file to be edited](https://github.com/pyjanitor-devs/pyjanitor/blob/dev/AUTHORS.md)

.github/pull_request_template.md

@@ -38,7 +38,7 @@ Please ensure that you have done the following:
 
 1. [ ] PR in from a fork off your branch. Do not PR from `<your_username>`:`dev`, but rather from `<your_username>`:`<feature-branch_name>`.
 <!-- Doing this helps us keep the commit history much cleaner than it would otherwise be. -->
-2. [ ] If you're not on the contributors list, add yourself to `AUTHORS.rst`.
+2. [ ] If you're not on the contributors list, add yourself to `AUTHORS.md`.
 <!-- We'd like to acknowledge your contributions! -->
 3. [ ] Add a line to `CHANGELOG.md` under the latest version header (i.e. the one that is "on deck") describing the contribution.
     - Do use some discretion here; if there are multiple PRs that are related, keep them in a single line.

MANIFEST.in

@@ -1,4 +1,3 @@
 include .requirements/*
-include *.rst
+include *.md
 include LICENSE
-include CHANGELOG.md