Fix CI builds with pytype in Python 3.8+

Author: seratch

scripts/install_all_and_run_tests.sh

@@ -22,5 +22,6 @@ else
     pip install -e ".[adapter]" && \
     black slack_bolt/ tests/ && \
     pytest && \
+    pip install -U pytype && \
     pytype slack_bolt/
 fi

scripts/run_pytype.sh

@@ -2,5 +2,7 @@
 # ./scripts/run_pytype.sh
 
 script_dir=$(dirname $0)
-cd ${script_dir}/..
-pip install -e ".[adapter]" && pytype slack_bolt/
+cd ${script_dir}/.. && \
+  pip install -e ".[adapter]" && \
+  pip install -U pytype && \
+  pytype slack_bolt/

scripts/run_tests.sh

@@ -20,6 +20,7 @@ else
     black slack_bolt/ tests/ \
       && pytest \
       && pip install -e ".[adapter]" \
+      && pip install -U pytype \
       && pytype slack_bolt/
   else
     black slack_bolt/ tests/ && pytest

setup.py

@@ -17,7 +17,6 @@
     "pytest-asyncio<1",  # for async
     "aiohttp>=3,<4",  # for async
     "black==19.10b0",
-    "pytype",
 ]
 
 setuptools.setup(