Bump default API version to 1.26

Signed-off-by: Joffrey F <joffrey@docker.com>

docker/constants.py

 import sys
 from .version import version
 
-DEFAULT_DOCKER_API_VERSION = '1.24'
+DEFAULT_DOCKER_API_VERSION = '1.26'
 MINIMUM_DOCKER_API_VERSION = '1.21'
 DEFAULT_TIMEOUT_SECONDS = 60
 STREAM_HEADER_SIZE_BYTES = 8

tests/integration/api_client_test.py

@@ -150,7 +150,7 @@ class UnixconnTest(unittest.TestCase):
         with warnings.catch_warnings(record=True) as w:
             warnings.simplefilter('always')
 
-            client = docker.APIClient(**kwargs_from_env())
+            client = docker.APIClient(version='auto', **kwargs_from_env())
             client.images()
             client.close()
             del client