enforce min py3.9 for setboard. create init.py in board-stubs

Author: FoamyGuy

Makefile

@@ -274,6 +274,7 @@ stubs:
 	@$(PYTHON) tools/board_stubs/build_board_specific_stubs/board_stub_builder.py
 	@cp -r tools/board_stubs/circuitpython_setboard circuitpython-stubs/circuitpython_setboard
 	@$(PYTHON) -m build circuitpython-stubs
+	@touch circuitpython-stubs/board/__init__.py
 
 .PHONY: check-stubs
 check-stubs: stubs

tools/board_stubs/circuitpython_setboard/__init__.py

@@ -35,6 +35,10 @@ def header(txt: str) -> str:
 
 
 def set_board():
+    version_info = sys.version_info
+    if version_info.major < 3 or (version_info.major == 3 and version_info.minor < 9):
+        sys.stdout.write("Python 3.9 is the minimum supported version for board specific stubs.\n")
+        sys.exit(0)
     parser = argparse.ArgumentParser(
         prog=__name__,
         usage="Install CircuitPython board-specific stubs",