[Go][Server] Time Parameters in the Path - Bug Fix

[icubbon]

Time parameters in the path resulted in code that would not compile as time was not imported.
Dynamically adding imports into the controller-api.mustache template based off of what parameter types are used is not implemented so parsing of time gets handled in the routers.go helpers.

This is probably a pretty rare case as it just seems weird to have a time path parameter, but it's good to fix.

Added an example to the Go-Server Petstore.yaml to show what this looks like.

This was introduced when time support was added in #16749

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@lwj5 @wing328

[lwj5]

@wing328 good to merge