Fix DeprecationWarning for locale.getdefaultlocale() in diagnose.py

Author: bluevisor

python/taichi/tools/diagnose.py

@@ -16,8 +16,9 @@ def main():
     print(f"platform: {platform.platform()}")
     print(f'architecture: {" ".join(platform.architecture())}')
     print(f"uname: {platform.uname()}")
-
-    print(f'locale: {".".join(locale.getdefaultlocale())}')
+    locale.setlocale(locale.LC_ALL, '')
+    loc, enc = locale.getlocale(), locale.getpreferredencoding()
+    print(f'locale: {loc[0]}.{enc if enc else loc[1]}')
     print(f'PATH: {os.environ.get("PATH")}')
     print(f"PYTHONPATH: {sys.path}")
     print("")