set pynini==2.1.5 (#167)

Author: makerjackie

setup.py

@@ -35,7 +35,7 @@
         "tn": ["*.fst"],
         "itn": ["*.fst"],
     },
-    install_requires=['pynini', 'importlib_resources'],
+    install_requires=['pynini==2.1.5', 'importlib_resources'],
     entry_points={
         "console_scripts": [
             "wetn = tn.main:main",