Release AdaNet v0.4.0.

PiperOrigin-RevId: 223386399

Author: cweill

Diff for: RELEASE.md

@@ -13,8 +13,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ==============================================================================-->
 
-# Current version (0.4.0-dev)
+# Current version (0.5.0-dev)
  * Under development.
+
+# Release 0.4.0
  * Add `shared` field to `adanet.Subnetwork` to deprecate, replace, and be more flexible than `persisted_tensors`.
  * Officially support multi-head learning with or without dict labels.
  * Rebuild the ensemble across iterations in Python without a frozen graph. This allows users to share more than `Tensors` between iterations including Python primitives, objects, and lambdas for greater flexibility. Eliminating reliance on a `MetaGraphDef` proto also eliminates I/O allowing for faster training, and better future-proofing.
@@ -41,4 +43,4 @@ limitations under the License.
  * Initial AdaNet release.
 
 ## Requirements
- * tf-nightly>=1.7.0.dev20180308 || tensorflow>=1.7.0rc0
+ * tf-nightly>=1.9.0.dev20180601 || tensorflow>=1.9.0rc0

Diff for: adanet/version.py

@@ -14,4 +14,4 @@
 # ==============================================================================
 """Contains the version string."""
 
-__version__ = "0.4.0-dev"
+__version__ = "0.4.0"