update to 8.12.0 LTS (#91)

Closes #90
diff --git a/core/nodejs8Action/CHANGELOG.md b/core/nodejs8Action/CHANGELOG.md
index af2376f..f931f87 100644
--- a/core/nodejs8Action/CHANGELOG.md
+++ b/core/nodejs8Action/CHANGELOG.md
@@ -19,7 +19,12 @@
 
 # NodeJS 8 OpenWhisk Runtime Container
 
-## 1.9.0
+## Apache 1.13 (next release)
+Change: Update Node.js
+
+Node.js version = [8.12.0](https://nodejs.org/en/blog/release/v8.12.0/)
+
+## 1.9.0 (Apache 1.12)
 Change: Update openwhisk npm package from `3.16.0` to `3.17.0`
 
 - [openwhisk v3.17.0](https://www.npmjs.com/package/openwhisk) - JavaScript client library for the OpenWhisk platform. Provides a wrapper around the OpenWhisk APIs.
diff --git a/core/nodejs8Action/Dockerfile b/core/nodejs8Action/Dockerfile
index 20e150a..bb218b2 100644
--- a/core/nodejs8Action/Dockerfile
+++ b/core/nodejs8Action/Dockerfile
@@ -15,7 +15,7 @@
 # limitations under the License.
 #
 
-FROM node:8.11.4
+FROM node:8.12.0
 RUN apt-get update && apt-get install -y \
     imagemagick \
     unzip \