Update to latest versions

Update base docker image to ubuntu-xenial
Update of-watchdog to 0.4.5

Signed-off-by: Burton Rheutan <rheutan7@gmail.com>

Author: burtonr

template/powershell-http/Dockerfile

@@ -1,6 +1,6 @@
-FROM microsoft/powershell:ubuntu16.04
+FROM microsoft/powershell:ubuntu-xenial
 
-RUN curl -sSLf https://github.com/openfaas-incubator/of-watchdog/releases/download/0.4.2/of-watchdog > /usr/bin/fwatchdog \
+RUN curl -sSLf https://github.com/openfaas-incubator/of-watchdog/releases/download/0.4.5/of-watchdog > /usr/bin/fwatchdog \
     && chmod +x /usr/bin/fwatchdog
 WORKDIR /root/