dev-python/typed-ast: Remove python 3.9

Python 3.9 is not yet supported in Chrome OS.

Error message:
Invalid implementation in PYTHON_COMPAT: python3_9

BUG=b:162009542
TEST=sudo emerge mypy

Change-Id: I460594f8787c6eaaf675ff990a4d0b5a4521b7d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2316392
Tested-by: Tom Hughes <tomhughes@chromium.org>
Auto-Submit: Tom Hughes <tomhughes@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Tom Hughes <tomhughes@chromium.org>
diff --git a/dev-python/typed-ast/typed-ast-1.4.1.ebuild b/dev-python/typed-ast/typed-ast-1.4.1.ebuild
index 2d0f36a..54fce9b 100644
--- a/dev-python/typed-ast/typed-ast-1.4.1.ebuild
+++ b/dev-python/typed-ast/typed-ast-1.4.1.ebuild
@@ -3,7 +3,7 @@
 
 EAPI=7
 
-PYTHON_COMPAT=( python3_{6,7,8,9} )
+PYTHON_COMPAT=( python3_{6,7,8} )
 inherit distutils-r1
 
 DESCRIPTION="Python typed-ast backported"