py-vermin: add latest version 1.3.1 (#26920)

* py-vermin: add latest version 1.3.1

* Exclude line from Vermin since version is already being checked for

Vermin 1.3.1 finds that `encoding` kwarg of builtin `open()` requires Python 3+.

lib/spack/llnl/util/tty/log.py

@@ -323,7 +323,7 @@ def unwrap(self):
                 if sys.version_info < (3,):
                     self.file = open(self.file_like, 'w')
                 else:
-                    self.file = open(self.file_like, 'w', encoding='utf-8')
+                    self.file = open(self.file_like, 'w', encoding='utf-8')  # novm
             else:
                 self.file = StringIO()
             return self.file