Fix vendoring for golang-http

Tested with a private Go module which was vendored, setting
GO111MODULE: off in build_args in stack.yml

I also created a nested package called pkg and referenced it
as "handler/function/pkg" from handler.go which worked as
expected.

Closes: #78

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Move to Go 1.17 for templates

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Switch to io from ioutil to read body

Tested with local docker build, also enables Go modules as a
default for golang-http, which was missing but meant to be
enabled via #63

Fixes #67

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Upgrade to of-watchdog 0.9.0

Introduces new quick shutdown mechanics.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Handle case when function is not a module

**What**
- Add check and skip when the funciton folder is not a module
Signed-off-by: Lucas Roesler <[email protected]>

Bump golang image version to 1.15-apline3.12

Signed-off-by: Vivek Singh <[email protected]>

Bump alpine version to 3.12

Signed-off-by: Vivek Singh <[email protected]>

Move to using templates-sdk repo for http function

The HTTP function now makes use of a dedicated repository
for SDK resources in the openfaas org.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

add query string example

Signed-off-by: Amal Alkhamees <[email protected]>

Update README.md