Update PHP 7.3 runtime to PHP 7.3.12
diff --git a/core/php7.3Action/CHANGELOG.md b/core/php7.3Action/CHANGELOG.md
index 4c44cf3..fe9c19c 100644
--- a/core/php7.3Action/CHANGELOG.md
+++ b/core/php7.3Action/CHANGELOG.md
@@ -18,7 +18,7 @@
 -->
 ## Apache 1.14.0 (next release)
 Changes:
-  - Update version of PHP to 7.3.6
+  - Update version of PHP to 7.3.12
   - Added PHP extension mongodb
   - Support getenv()
 
diff --git a/core/php7.3Action/Dockerfile b/core/php7.3Action/Dockerfile
index d601299..b77198c 100644
--- a/core/php7.3Action/Dockerfile
+++ b/core/php7.3Action/Dockerfile
@@ -25,7 +25,7 @@
 #  && cd src/github.com/apache/incubator-openwhisk-runtime-go/main \
 #  && CGO_ENABLED=0 go build -o /bin/proxy
 
-FROM php:7.3.6-cli-stretch
+FROM php:7.3.12-cli-stretch
 
 # install dependencies
 RUN \