updated release notes [skip ci] (#1955)

Author: devjgm

google/cloud/README.md

@@ -22,7 +22,14 @@ is available [online][doxygen-link].
 
 ## Release Notes
 
-### v0.4.x - TBD
+### v0.5.x - TBD
+
+### v0.4.x - 2019-02
+
+* Fixed some documentation.
+* **Breaking change**: Removed `StatusOr<void>`.
+* Updated `StatusOr` documentation.
+* Fixed some (minor) issues found by coverity.
 
 ### v0.3.x - 2019-01
 

google/cloud/bigtable/README.md

@@ -21,7 +21,20 @@ is available [online][doxygen-link].
 
 ## Release Notes
 
-### v0.6.x - TBD
+### v0.7.x - TBD
+
+### v0.6.x - 2019-02
+
+* Moved repo organization from GoogleCloudPlatform -> googleapis.
+* Implemented several more async functions.
+* **Breaking change**: Started migrating functions to `StatusOr` and away from
+  throwing exceptions.
+* Several fixes to bulk mutator (#1880)
+* Disabled `make install` for external projects.
+* `Row` now has a move constructor.
+* Increased default message length limit.
+* Now testing build with libc++ on Linux.
+* Fixed some bugs found by Coverity scans.
 
 ### v0.5.x - 2019-01
 

google/cloud/storage/README.md

@@ -20,7 +20,26 @@ the reference guide includes a quick start guide.
 
 ## Release Notes
 
-### v0.4.x - TBD
+### v0.5.x - TBD
+
+### v0.4.x - 2019-02
+
+* **Breaking change**: Removed almost all exception throwing in favor of
+  `StatusOr<T>` return values.
+* Lots of cleanup to documentation and example code.
+* Avoids use of `StatusOr::value()` when the validity was already checked.
+* `Client::ListBuckets()` now directly returns `ListBucketsReader`, because it
+  cannot fail so `StatusOr` was not needed.
+* Removed support for `StatusOr<void>`; changed usages to return `Status`
+  instead.
+* 502s are now retryable errors from GCS.
+* **Breaking change**: `LockBucketRetentionPolicy` returns a `BucketMetadata`
+  now instead of `void`.
+* Cleaned up documentation and example code.
+* Disabled `make install` for external projects.
+* Moved repo organization from GoogleCloudPlatform -> googleapis.
+* Moved some internal-only APIs out of public interfaces.
+* Fixed resuming uploads when the server responds with a 308.
 
 ### v0.3.x - 2019-01