bump version and changelog for 2.3 release (#4356)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 5ac43d0..12c4d65 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -3,10 +3,8 @@
 
 .. _v2-3:
 
-2.3 - `master`_
-~~~~~~~~~~~~~~~
-
-.. note:: This version is not yet released and is under active development.
+2.3 - 2018-07-18
+~~~~~~~~~~~~~~~~
 
 * **SECURITY ISSUE:**
   :meth:`~cryptography.hazmat.primitives.ciphers.AEADDecryptionContext.finalize_with_tag`
diff --git a/src/cryptography/__about__.py b/src/cryptography/__about__.py
index b198409..935e656 100644
--- a/src/cryptography/__about__.py
+++ b/src/cryptography/__about__.py
@@ -14,7 +14,7 @@
                " and primitives to Python developers.")
 __uri__ = "https://github.com/pyca/cryptography"
 
-__version__ = "2.3.dev1"
+__version__ = "2.3"
 
 __author__ = "The cryptography developers"
 __email__ = "cryptography-dev@python.org"
diff --git a/vectors/cryptography_vectors/__about__.py b/vectors/cryptography_vectors/__about__.py
index d15f1ab..8f73dc7 100644
--- a/vectors/cryptography_vectors/__about__.py
+++ b/vectors/cryptography_vectors/__about__.py
@@ -14,7 +14,7 @@
 
 __uri__ = "https://github.com/pyca/cryptography"
 
-__version__ = "2.3.dev1"
+__version__ = "2.3"
 
 __author__ = "The cryptography developers"
 __email__ = "cryptography-dev@python.org"