Detect changes in external modules' subpackages
Previously patrol would only catch a dependency upgrade in go.mod if a
local package was referring the top-level package in that dependency.
For example if your go.mod looked something like:
module github.com/your-org/your-module
go 1.17
require github.com/another-org/their-module v1.8.0
And you were to upgrade github.com/another-org/their-module to version
v1.8.1, only the packages in your module relying on
github.com/another-org/their-module would be marked as changed, while
packages depending on other nested package in that dependency wouldn't
(e.g. github.com/another-org/their-module/writer).