Repository: docker/docker-py

Issue:
Old default value for API version in documentation
In documentation, there is old default value for API version (`1.24`), but [in constants.py](https://github.com/docker/docker-py/blob/master/docker/client.py#L61) there is `DEFAULT_DOCKER_API_VERSION = '1.26'` (which is actually used as a default).

[documentation latest/client](http://docker-py.readthedocs.io/en/latest/client.html):
```
 from_env()
    Return a client configured from environment variables.
    The environment variables used are the same as those used by the Docker command-line client. They are:
    DOCKER_HOST
        The URL to the Docker host.
    DOCKER_TLS_VERIFY
        Verify the host against a CA certificate.
    DOCKER_CERT_PATH
        A path to a directory containing TLS certificates to use when connecting to the Docker host.
    Parameters:	
        version (str) – The version of the API to use. Set to auto to automatically detect the server’s version. Default: 1.24
```

[client.py](https://github.com/docker/docker-py/blob/master/docker/client.py#L61):
```python
 @classmethod
    def from_env(cls, **kwargs):
        """
        Return a client configured from environment variables.
        The environment variables used are the same as those used by the
        Docker command-line client. They are:
        .. envvar:: DOCKER_HOST
            The URL to the Docker host.
        .. envvar:: DOCKER_TLS_VERIFY
            Verify the host against a CA certificate.
        .. envvar:: DOCKER_CERT_PATH
            A path to a directory containing TLS certificates to use when
            connecting to the Docker host.
        Args:
            version (str): The version of the API to use. Set to ``auto`` to
                automatically detect the server's version. Default: ``1.24``
            timeout (int): Default timeout for API calls, in seconds.
            ssl_version (int): A valid `SSL version`_.
            assert_hostname (bool): Verify the hostname of the server.
            environment (dict): The environment to read environment variables
                from. Default: the value of ``os.environ``
```




Discussion:

Resolving patch:
diff --git a/docker/api/client.py b/docker/api/client.py
--- a/docker/api/client.py
+++ b/docker/api/client.py
@@ -75,7 +75,7 @@ class APIClient(
         base_url (str): URL to the Docker server. For example,
             ``unix:///var/run/docker.sock`` or ``tcp://127.0.0.1:1234``.
         version (str): The version of the API to use. Set to ``auto`` to
-            automatically detect the server's version. Default: ``1.24``
+            automatically detect the server's version. Default: ``1.26``
         timeout (int): Default timeout for API calls, in seconds.
         tls (bool or :py:class:`~docker.tls.TLSConfig`): Enable TLS. Pass
             ``True`` to enable it with default options, or pass a
diff --git a/docker/client.py b/docker/client.py
--- a/docker/client.py
+++ b/docker/client.py
@@ -24,7 +24,7 @@ class DockerClient(object):
         base_url (str): URL to the Docker server. For example,
             ``unix:///var/run/docker.sock`` or ``tcp://127.0.0.1:1234``.
         version (str): The version of the API to use. Set to ``auto`` to
-            automatically detect the server's version. Default: ``1.24``
+            automatically detect the server's version. Default: ``1.26``
         timeout (int): Default timeout for API calls, in seconds.
         tls (bool or :py:class:`~docker.tls.TLSConfig`): Enable TLS. Pass
             ``True`` to enable it with default options, or pass a
@@ -58,7 +58,7 @@ def from_env(cls, **kwargs):
 
         Args:
             version (str): The version of the API to use. Set to ``auto`` to
-                automatically detect the server's version. Default: ``1.24``
+                automatically detect the server's version. Default: ``1.26``
             timeout (int): Default timeout for API calls, in seconds.
             ssl_version (int): A valid `SSL version`_.
             assert_hostname (bool): Verify the hostname of the server.


Test patch: