[docs] fixed PyPI version badge (#1319)

* fixed PyPI badge

* Update Parameters.rst

* Update Parameters.rst

* Update Parameters.rst

README.md

@@ -7,7 +7,7 @@ LightGBM, Light Gradient Boosting Machine
 [![GitHub Issues](https://img.shields.io/github/issues/Microsoft/LightGBM.svg)](https://github.com/Microsoft/LightGBM/issues)
 [![License](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/Microsoft/LightGBM/blob/master/LICENSE)
 [![Python Versions](https://img.shields.io/pypi/pyversions/lightgbm.svg)](https://pypi.python.org/pypi/lightgbm)
-[![PyPI Version](https://badge.fury.io/py/lightgbm.svg)](https://badge.fury.io/py/lightgbm)
+[![PyPI Version](https://img.shields.io/pypi/v/lightgbm.svg)](https://pypi.python.org/pypi/lightgbm)
 [![Join the chat at https://gitter.im/Microsoft/LightGBM](https://badges.gitter.im/Microsoft/LightGBM.svg)](https://gitter.im/Microsoft/LightGBM?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Slack](https://lightgbm-slack-autojoin.herokuapp.com/badge.svg)](https://lightgbm-slack-autojoin.herokuapp.com/)
 

docs/Parameters.rst

@@ -576,9 +576,9 @@ Objective Parameters
 Metric Parameters
 -----------------
 
--  ``metric``, default=\ ``""``, type=multi-enum
+-  ``metric``, default=\ ``''``, type=multi-enum
 
-   -  if ``""``(empty string or not specific), metric corresponding to specified application will be used
+   -  if \ ``''`` (empty string or not specific), metric corresponding to specified application will be used
 
    -  ``l1``, absolute loss, alias=\ ``mean_absolute_error``, ``mae``, ``regression_l1``
 

python-package/README.rst

@@ -157,5 +157,5 @@ E501 can be ignored (line too long).
    :target: https://github.com/Microsoft/LightGBM/blob/master/LICENSE
 .. |Python Versions| image:: https://img.shields.io/pypi/pyversions/lightgbm.svg
    :target: https://pypi.python.org/pypi/lightgbm
-.. |PyPI Version| image:: https://badge.fury.io/py/lightgbm.svg
-   :target: https://badge.fury.io/py/lightgbm
+.. |PyPI Version| image:: https://img.shields.io/pypi/v/lightgbm.svg
+   :target: https://pypi.python.org/pypi/lightgbm