DOC: Update development documentation urls (#26857)

Author: datapythonista

README.md

@@ -224,7 +224,7 @@ Most development discussion is taking place on github in this repo. Further, the
 
 All contributions, bug reports, bug fixes, documentation improvements, enhancements and ideas are welcome.
 
-A detailed overview on how to contribute can be found in the **[contributing guide](https://pandas-docs.github.io/pandas-docs-travis/contributing.html)**. There is also an [overview](.github/CONTRIBUTING.md) on GitHub.
+A detailed overview on how to contribute can be found in the **[contributing guide](https://dev.pandas.io/contributing.html)**. There is also an [overview](.github/CONTRIBUTING.md) on GitHub.
 
 If you are simply looking to start working with the pandas codebase, navigate to the [GitHub "issues" tab](https://github.com/pandas-dev/pandas/issues) and start looking through interesting issues. There are a number of issues listed under [Docs](https://github.com/pandas-dev/pandas/issues?labels=Docs&sort=updated&state=open) and [good first issue](https://github.com/pandas-dev/pandas/issues?labels=good+first+issue&sort=updated&state=open) where you could start out.
 

doc/source/development/contributing.rst

@@ -460,7 +460,7 @@ Building master branch documentation
 
 When pull requests are merged into the *pandas* ``master`` branch, the main parts of
 the documentation are also built by Travis-CI. These docs are then hosted `here
-<http://pandas-docs.github.io/pandas-docs-travis>`__, see also
+<https://dev.pandas.io>`__, see also
 the :ref:`Continuous Integration <contributing.ci>` section.
 
 .. _contributing.code:

doc/source/whatsnew/v0.25.0.rst

@@ -411,7 +411,7 @@ If installed, we now require:
 | pytest (dev)    | 4.0.2           |          |
 +-----------------+-----------------+----------+
 
-For `optional libraries <https://pandas-docs.github.io/pandas-docs-travis/install.html#dependencies>`_ the general recommendation is to use the latest version.
+For `optional libraries <https://dev.pandas.io/install.html#dependencies>`_ the general recommendation is to use the latest version.
 The following table lists the lowest version per library that is currently being tested throughout the development of pandas.
 Optional libraries below the lowest tested version may still work, but are not considered supported.