Dropped support for really old macOS (#3554)

* Dropped support for really old macOS

Fixes #3503

* literally, how does spelling
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 2961ead..176ad3c 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -6,15 +6,16 @@
 
 .. note:: This version is not yet released and is under active development.
 
-* Add support for providing ``tag`` during
-  :class:`~cryptography.hazmat.primitives.ciphers.modes.GCM` finalization via
-  :meth:`~cryptography.hazmat.primitives.ciphers.AEADDecryptionContext.finalize_with_tag`.
 * **BACKWARDS INCOMPATIBLE:** Elliptic Curve signature verification no long
   returns ``True`` on success. This brings it in line with the interface's
   documentation, and our intent. The correct way to use
   :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.verify`
   has always been to check whether or not
   :class:`~cryptography.exceptions.InvalidSignature` was raised.
+* **BACKWARDS INCOMPATIBLE:** Dropped support for macOS 10.7 and 10.8.
+* Add support for providing ``tag`` during
+  :class:`~cryptography.hazmat.primitives.ciphers.modes.GCM` finalization via
+  :meth:`~cryptography.hazmat.primitives.ciphers.AEADDecryptionContext.finalize_with_tag`.
 * Fixed an issue preventing ``cryptography`` from compiling against
   LibreSSL 2.5.x.
 * Accessing an unrecognized extension marked critical on an X.509 object will
diff --git a/docs/installation.rst b/docs/installation.rst
index e56d66c..9ee966a 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -15,8 +15,7 @@
 
 * x86-64 CentOS 7.x, 6.4
 * x86-64 FreeBSD 10
-* macOS 10.12 Sierra, 10.11 El Capitan, 10.10 Yosemite, 10.9 Mavericks,
-  10.8 Mountain Lion, and 10.7 Lion
+* macOS 10.12 Sierra, 10.11 El Capitan, 10.10 Yosemite, 10.9 Mavericks
 * x86-64 Ubuntu 12.04 LTS and Ubuntu 14.04 LTS
 * x86-64 Debian Wheezy (7.x), Jessie (8.x), and Debian Sid (unstable)
 * 32-bit and 64-bit Python on 64-bit Windows Server 2012