pip(deps): bump moto from 2.2.15 to 2.2.19

Bumps [moto](https://github.com/spulec/moto) from 2.2.15 to 2.2.19.
- [Release notes](https://github.com/spulec/moto/releases)
- [Changelog](https://github.com/spulec/moto/blob/master/CHANGELOG.md)
- [Commits](getmoto/moto@2.2.15...2.2.19)

---
updated-dependencies:
- dependency-name: moto
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements/DEV_REQUIREMENTS.txt

@@ -2,8 +2,9 @@ black==21.10b0
 coveralls==3.3.1
 coverage==6.1.2
 isort==5.10.1
-moto==2.2.15
-portray==1.7.0
+moto==2.2.19
+pydoc-markdown==4.3.2 ; python_version >= '3.7'
+pydoc-markdown==3.13.0 ; python_version == '3.6'
 pytest==6.2.5
 pytest-cov==3.0.0
 pylint==2.11.1