[util] fixed check_tool_requirements.py shebang

Signed-off-by: Arnon Sharlin <arnon.sharlin@opentitan.org>
diff --git a/util/check_tool_requirements.py b/util/check_tool_requirements.py
index 77c469c..5c1d386 100755
--- a/util/check_tool_requirements.py
+++ b/util/check_tool_requirements.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 # Copyright lowRISC contributors.
 # Licensed under the Apache License, Version 2.0, see LICENSE for details.
 # SPDX-License-Identifier: Apache-2.0