infra: add doc8 check for documentation files (#1441)

Author: laurenyu

buildspec-release.yml

@@ -13,8 +13,7 @@ phases:
       - tox -e black-check
 
       # run package and docbuild checks
-      - tox -e twine
-      - tox -e sphinx
+      - tox -e twine,sphinx,doc8
 
       # run unit tests
       - AWS_ACCESS_KEY_ID= AWS_SECRET_ACCESS_KEY= AWS_SESSION_TOKEN=

buildspec-unittests.yml

@@ -11,8 +11,8 @@ phases:
       - ./ci-scripts/displaytime.sh 'flake8,pylint,twine,black-check' $start_time
 
       - start_time=`date +%s`
-      - tox -e sphinx
-      - ./ci-scripts/displaytime.sh 'sphinx' $start_time
+      - tox -e sphinx,doc8
+      - ./ci-scripts/displaytime.sh 'sphinx,doc8' $start_time
 
       # run unit tests
       - start_time=`date +%s`