all: remove dep source for govalidator (#1638)

Remove the `source` parameter for the `github.com/asaskevich/govalidator` dependency in the dep Gopkg.* files.

This change is being made to simplify the `go.mod` file that will be generated when we move to Modules (#1634).

The `source` parameter for the `github.com/asaskevich/govalidator` dependency is pointing to the same repository as the dependency name, just with a `.git` extension. GitHub treats the two repository URLs the same and it was probably an error that we set the source to that value. The presence of the `source` parameter causes `go mod init` when converting from go dep to go modules to think the `source` is pointing to a fork which adds an extra unnecessary `replace` directive to the the `go.mod` file that is generated.

This change is expected to be a no-op on existing functionality and on the dependencies that get pulled in during a build as it should cause no changes to the dependencies that `dep` pulls in.

Author: leighmcculloch

Gopkg.lock

@@ -3,8 +3,8 @@
   name = "bitbucket.org/ww/goautoneg"
 
 [[constraint]]
+  branch = "master"
   name = "github.com/asaskevich/govalidator"
-  source = "https://github.com/asaskevich/govalidator.git"
 
 [[constraint]]
   name = "github.com/go-chi/chi"