update black target version (Cog-Creators#3300)

Author: mikeshardmind

Makefile

@@ -2,9 +2,9 @@ PYTHON ?= python3.8
 
 # Python Code Style
 reformat:
-	$(PYTHON) -m black -l 99 --target-version py37 `git ls-files "*.py"`
+	$(PYTHON) -m black -l 99 --target-version py38 `git ls-files "*.py"`
 stylecheck:
-	$(PYTHON) -m black --check -l 99 --target-version py37 `git ls-files "*.py"`
+	$(PYTHON) -m black --check -l 99 --target-version py38 `git ls-files "*.py"`
 
 # Translations
 gettext:

make.bat

@@ -14,11 +14,11 @@ for /F "tokens=* USEBACKQ" %%A in (`git ls-files "*.py"`) do (
 goto %1
 
 :reformat
-black -l 99 --target-version py37 !PYFILES!
+black -l 99 --target-version py38 !PYFILES!
 exit /B %ERRORLEVEL%
 
 :stylecheck
-black -l 99 --check --target-version py37 !PYFILES!
+black -l 99 --check --target-version py38 !PYFILES!
 exit /B %ERRORLEVEL%
 
 :newenv