update documentation links with stable version 'engine-2.3'

README.md

@@ -17,22 +17,22 @@ suggestions and criticisms from the community are always very welcome.
 ## Documentation
 
 * [Source Code/API Documentation](http://docs.openquake.org/oq-hazardlib/)
-* [Continuous integration and testing](https://github.com/gem/oq-hazardlib/blob/master/doc/testing.md)
+* [Continuous integration and testing](https://github.com/gem/oq-hazardlib/blob/engine-2.3/doc/testing.md)
 
 ### Installation
 
-* [Technology stack and requirements](https://github.com/gem/oq-hazardlib/blob/master/doc/requirements.md)
-* [Installing from sources](https://github.com/gem/oq-hazardlib/blob/master/doc/development.md)
+* [Technology stack and requirements](https://github.com/gem/oq-hazardlib/blob/engine-2.3/doc/requirements.md)
+* [Installing from sources](https://github.com/gem/oq-hazardlib/blob/engine-2.3/doc/development.md)
 
-The OpenQuake Hazardlib is also distributed in the form of **binary package** for Linux, macOS and Windows as part of the [OpenQuake Engine](https://github.com/gem/oq-engine/) suite. See the [OpenQuake Engine README](https://github.com/gem/oq-engine/blob/master/README.md#installation) for more information.
+The OpenQuake Hazardlib is also distributed in the form of **binary package** for Linux, macOS and Windows as part of the [OpenQuake Engine](https://github.com/gem/oq-engine/) suite. See the [OpenQuake Engine README](https://github.com/gem/oq-engine/blob/engine-2.3/README.md#installation) for more information.
 
 ### Development
 
-* [Implementing a new GSIM](https://github.com/gem/oq-hazardlib/blob/master/doc/implementing-new-gsim.md)
+* [Implementing a new GSIM](https://github.com/gem/oq-hazardlib/blob/engine-2.3/doc/implementing-new-gsim.md)
 
 ## License
 
-The OpenQuake Hazardlib is released under the **[GNU Affero Public License 3](https://github.com/gem/oq-hazardlib/blob/master/LICENSE)**.
+The OpenQuake Hazardlib is released under the **[GNU Affero Public License 3](https://github.com/gem/oq-hazardlib/blob/engine-2.3/LICENSE)**.
 
 ## Contacts
 

doc/sphinx/intro.rst

@@ -33,7 +33,7 @@ support on IRC channel #openquake on freenode.
 Installation
 ------------
 
-See https://github.com/gem/oq-hazardlib/blob/master/README.md#installation
+See https://github.com/gem/oq-hazardlib/blob/engine-2.3/README.md#installation
 
 License
 -------