Use python3

python2 is EOL, specify the python scripts to use python3.

Tested: Verify it builds fine in local CI. With bitbake recipe changes,
        verify it builds OK with python3native.

Signed-off-by: Lei YU <mine260309@gmail.com>
Change-Id: Icd5d10193e9323bbdbcd854e9027e014e01a1829
diff --git a/meson.build b/meson.build
index 9cfb46c..92c1450 100644
--- a/meson.build
+++ b/meson.build
@@ -33,7 +33,7 @@
 gtest = dependency('gtest', main: true, disabler: true, required: build_tests)
 phosphor_dbus_interfaces = dependency('phosphor-dbus-interfaces')
 phosphor_logging = dependency('phosphor-logging')
-prog_python = import('python').find_installation('python')
+prog_python = import('python').find_installation('python3')
 sdbusplus = dependency('sdbusplus')
 sdbuspp = find_program('sdbus++')
 sdeventplus = dependency('sdeventplus')
diff --git a/phosphor-regulators/tools/validate-regulators-config.py b/phosphor-regulators/tools/validate-regulators-config.py
index bca989d..7b1cd6f 100755
--- a/phosphor-regulators/tools/validate-regulators-config.py
+++ b/phosphor-regulators/tools/validate-regulators-config.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import argparse
 import json
diff --git a/power-sequencer/gen-ucd90160-defs.py b/power-sequencer/gen-ucd90160-defs.py
index 1eb0d06..b191ef6 100755
--- a/power-sequencer/gen-ucd90160-defs.py
+++ b/power-sequencer/gen-ucd90160-defs.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import os
 import yaml