fix: update file watch to trigger callback after symbolic link changes

[jondavidnd1]

This fixes issue 323. The changes are based mostly on similar code found in the viper codebase.

[jondavidnd1]

Sorry, I didn't want to stack too many commits so I closed the old PR and started from scratch. Apologies for not originally seeing the watch tests. I have added an additional watch test to mimic what kubernetes does and validated that the test is successful on my branch and failed without my changes (I did have to add a waitTimeout function otherwise the tests just hung waiting for the watch trigger).

[jondavidnd1]

@knadh not urgent, but would appreciate a review when you have a chance. Thanks.

[knadh]

Released as providers/file/v1.1.1. Thanks for the PR!

[jondavidnd1]

Released as providers/file/v1.1.1. Thanks for the PR!

You're welcome, and thanks for the great library.

[jondavidnd1]

Released as providers/file/v1.1.1. Thanks for the PR!

@knadh , perhaps I misunderstood, the changes are now on master but they don't appear to be in that tag (providers/file/v1.1.1 created last week).

[knadh]

Sorry, it's v1.1.2 - https://github.com/knadh/koanf/releases/tag/providers%2Ffile%2Fv1.1.2