all: bump to v0.50.0

This commit will be tagged v0.50.0.

Change-Id: I8367df45abb88ebd46b74c104cf4d962684ba4a0
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/49670
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Cody Oss <codyoss@google.com>
diff --git a/CHANGES.md b/CHANGES.md
index 289eac4..a38da88 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,15 @@
 # Changes
 
+## v0.50.0
+
+- profiler:
+  - Support disabling CPU profile collection.
+  - Log when a profile creation attempt begins.
+- compute/metadata:
+  - Fix panic on malformed URLs.
+  - InstanceName returns actual instance name.
+- Various updates to autogenerated clients.
+
 ## v0.49.0
 
 - functions/metadata: