Promote ip-masq-agent:v2.12.0.

Author: MrHohn

registry.k8s.io/images/k8s-staging-networking/images.yaml

@@ -1,5 +1,6 @@
 - name: ip-masq-agent
   dmap:
+    "sha256:ea696f45c75fde5d2239b457520bbf2f71465467136d4238e4549d8464b61848": ["v2.12.0"]
     "sha256:83421f512159001b65f0d17d236b9bec7b5f742a420cea229cca5c90d696247a": ["v2.9.3"]
     "sha256:b67564f4370887d0a744410786d3c9a262b3e38ddce83a58b1189710bea065a8": ["v2.9.2"]
     "sha256:bb14c14b7a829909ec3e76bc0137269b9e52c4353522f9a5156e3f7903e4cdbe": ["v2.9.0"]