chroot hooks: add 189_purge_pypy

Force a rebuild of pypy3.

BUG=b:204077219, b:201487405, b:187793277
TEST=chromiumos-sdk-tryjob

Change-Id: Ic805966c9282466db499deb49cc3f9d4b6b7f1fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3243334
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Tested-by: Lizzy Presland <zland@google.com>
Auto-Submit: Lizzy Presland <zland@google.com>
Commit-Queue: Lizzy Presland <zland@google.com>
diff --git a/chroot_version_hooks.d/189_purge_pypy b/chroot_version_hooks.d/189_purge_pypy
new file mode 100644
index 0000000..35ac2ed
--- /dev/null
+++ b/chroot_version_hooks.d/189_purge_pypy
@@ -0,0 +1,7 @@
+# Copyright 2021 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Force rebuild of pypy3 to ensure portage picks up changes that cause byte
+# compilation of pypy3 libs.
+sudo emerge --rage-clean pypy3