openssl 1.1.1 testing (#4112)

* test openssl 1.1.1

* let's see what a 1.1.1 pyopenssl does

* 1.1.1-pre8

* pre9

* docs and test more things

* 3.7 needs xenial
diff --git a/.travis.yml b/.travis.yml
index efee367..a14ecf4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -41,6 +41,12 @@
           env: TOXENV=py27 OPENSSL=1.1.0h
         - python: 3.5
           env: TOXENV=py35 OPENSSL=1.1.0h
+        - python: 2.7
+          env: TOXENV=py27 OPENSSL=1.1.1-pre9
+        - python: 3.7
+          env: TOXENV=py37 OPENSSL=1.1.1-pre9
+          dist: xenial
+          sudo: true
         - python: 3.6
           env: TOXENV=py36 LIBRESSL=2.4.5
         - python: 3.6
diff --git a/docs/installation.rst b/docs/installation.rst
index a4649f5..d665dbc 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -28,6 +28,7 @@
 * ``OpenSSL 1.0.1f``
 * ``OpenSSL 1.0.2-latest``
 * ``OpenSSL 1.1.0-latest``
+* ``OpenSSL 1.1.1-latest``
 
 Building cryptography on Windows
 --------------------------------