build proxy from openwhisk-runtime-go 1.16.0 release (#122)

diff --git a/core/swift42Action/Dockerfile b/core/swift42Action/Dockerfile
index 064a59e..d58f619 100644
--- a/core/swift42Action/Dockerfile
+++ b/core/swift42Action/Dockerfile
@@ -21,7 +21,7 @@
 
 # or build it from a release
 FROM golang:1.15 AS builder_release
-ARG GO_PROXY_RELEASE_VERSION=1.12@1.15.0
+ARG GO_PROXY_RELEASE_VERSION=1.15@1.16.0
 RUN curl -sL \
   https://github.com/apache/openwhisk-runtime-go/archive/{$GO_PROXY_RELEASE_VERSION}.tar.gz\
   | tar xzf -\
diff --git a/core/swift51Action/Dockerfile b/core/swift51Action/Dockerfile
index 99f035f..65e2b1d 100644
--- a/core/swift51Action/Dockerfile
+++ b/core/swift51Action/Dockerfile
@@ -21,7 +21,7 @@
 
 # or build it from a release
 FROM golang:1.15 AS builder_release
-ARG GO_PROXY_RELEASE_VERSION=1.12@1.15.0
+ARG GO_PROXY_RELEASE_VERSION=1.15@1.16.0
 RUN curl -sL \
   https://github.com/apache/openwhisk-runtime-go/archive/{$GO_PROXY_RELEASE_VERSION}.tar.gz\
   | tar xzf -\