Match components using path prefixes, not string prefixes.

[charypar]

When filtering changed files to components (https://github.com/charypar/monobuild/blob/104deb915d1c466d68afd5aa520f769a6b9e12ae/manifests/manifests.go#L144) the paths are matched on a sub-string. This sometimes mismatches components if they share a common sub-string (e.g. my-component and my-component-v2).

The correct way is to split the path to individual segments and look for a sub-list.

This is also the cause of issue fixed by https://github.com/charypar/monobuild/pull/18.