Update metadata for azure-identity 1.6.0 release (Azure#18669)

Author: chlowell

sdk/identity/azure-identity/CHANGELOG.md

@@ -1,13 +1,21 @@
 # Release History
 
-## 1.6.0b4 (Unreleased)
+## 1.6.0 (2021-05-13)
+This is the last version to support Python 3.5. The next version will require
+Python 2.7 or 3.6+.
+
 ### Added
 - `AzurePowerShellCredential` authenticates as the identity logged in to Azure
   PowerShell. This credential is part of `DefaultAzureCredential` by default
   but can be disabled by a keyword argument:
   `DefaultAzureCredential(exclude_powershell_credential=True)`
   ([#17341](https://github.com/Azure/azure-sdk-for-python/issues/17341))
 
+### Fixed
+- `AzureCliCredential` raises `CredentialUnavailableError` when the CLI times out,
+  and kills timed out subprocesses
+- Reduced retry delay for `ManagedIdentityCredential` on Azure VMs
+
 ## 1.6.0b3 (2021-04-06)
 ### Breaking Changes
 > These changes do not impact the API of stable versions such as 1.5.0.

sdk/identity/azure-identity/azure/identity/_version.py

@@ -2,4 +2,4 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 # ------------------------------------
-VERSION = "1.6.0b4"
+VERSION = "1.6.0"

sdk/identity/azure-identity/setup.py

@@ -52,7 +52,7 @@
     author_email="[email protected]",
     url="https://github.com/Azure/azure-sdk-for-python/tree/master/sdk/identity/azure-identity",
     classifiers=[
-        "Development Status :: 4 - Beta",
+        "Development Status :: 5 - Production/Stable",
         "Programming Language :: Python",
         "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",