feat: Python 3.9 for readthedocs (#2973)

Co-authored-by: Ben Crabtree <bencrab@amazon.com>
Co-authored-by: Navin Soni <navinsoni89@gmail.com>
Co-authored-by: Jeniya Tabassum <jeniya.tabassum@gmail.com>
Co-authored-by: Dewen Qi <qidewen@amazon.com>
Co-authored-by: Payton Staub <pstaub@amazon.com>
Co-authored-by: qidewenwhen <32910701+qidewenwhen@users.noreply.github.com>
Co-authored-by: Qingzi-Lan <83724147+Qingzi-Lan@users.noreply.github.com>
Co-authored-by: Payton Staub <staubhpa@gmail.com>

Author: 9 people

.readthedocs.yml

@@ -5,7 +5,7 @@
 version: 2
 
 python:
-  version: 3.6
+  version: 3.9
   install:
     - method: pip
       path: .

doc/conf.py

@@ -10,7 +10,7 @@
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
 # ANY KIND, either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
-"""Placeholder docstring"""
+"""Configuration for generating readthedocs docstrings."""
 from __future__ import absolute_import
 
 import pkg_resources