Merge branch 'nanonyme/news-1.6.1' into 'bst-1'

Prepare for 1.6.1

See merge request BuildStream/buildstream!2096
diff --git a/NEWS b/NEWS
index 64e1bf7..6158e3c 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,10 @@
 =================
+buildstream 1.6.1
+=================
+
+  o Fix failure handling with CAS (#1403)
+
+=================
 buildstream 1.6.0
 =================
 
diff --git a/setup.py b/setup.py
index a214fa5..5f934d0 100755
--- a/setup.py
+++ b/setup.py
@@ -261,6 +261,8 @@
           'Programming Language :: Python :: 3.5',
           'Programming Language :: Python :: 3.6',
           'Programming Language :: Python :: 3.7',
+          'Programming Language :: Python :: 3.8',
+          'Programming Language :: Python :: 3.9',
           'Topic :: Software Development :: Build Tools'
       ],
       description='A framework for modelling build pipelines in YAML',