Point to correct docker version for stable

Author: stsewd

docs/config-file/v2.rst

@@ -177,7 +177,7 @@ The build Docker image to be used.
 Each image support different Python versions and has different packages installed,
 as defined here:
 
-* `stable <https://github.com/rtfd/readthedocs-docker-images/tree/3.0.0>`_: 2, 2.7, 3, 3.3, 3.4, 3.5, 3.6
+* `stable <https://github.com/rtfd/readthedocs-docker-images/tree/releases/2.x>`_: 2, 2.7, 3, 3.3, 3.4, 3.5, 3.6
 * `latest <https://github.com/rtfd/readthedocs-docker-images/tree/releases/3.x>`_: 2, 2.7, 3, 3.3, 3.4, 3.5, 3.6
 
 sphinx