Update dependency keyrings.alt to v3.1 (#2773)

renovate[bot] · takirala · commit 642f654a2ab0 · 2018-12-13T13:44:16.000-08:00
diff --git a/frozen_requirements.txt b/frozen_requirements.txt
@@ -63,7 +63,7 @@ jeepney==0.4
 jmespath==0.9.3
 jsonschema==2.6.0
 keyring==15.1.0
-keyrings.alt==3.0
+keyrings.alt==3.1
 lazy-object-proxy==1.3.1
 macholib==1.11
 mccabe==0.6.1
