fix: bug fix mypy issues on Github Actions

Author: shreraju-amzn

tox.ini

@@ -29,6 +29,9 @@ commands =
     python -m pip install --upgrade pip
     python -m pip install --upgrade wheel
     py{36,37,38}: python -m pip install --upgrade mypy
+    python -m pip install types-python-dateutil
+    python -m pip install types-requests
+    python -m pip install types-six
     {toxinidir}/scripts/ci/sdk_install
     {toxinidir}/scripts/ci/run_tests
     py{36,37,38}: mypy ask-sdk/ask_sdk
@@ -57,6 +60,9 @@ commands =
     python -m pip install --upgrade pip
     python -m pip install --upgrade wheel
     py{36,37,38}: python -m pip install --upgrade mypy
+    python -m pip install types-python-dateutil
+    python -m pip install types-requests
+    python -m pip install types-six
     python {toxinidir}\scripts\ci\sdk_install
     python {toxinidir}\scripts\ci\run_tests
     mypy ask-sdk\ask_sdk