## Changes
This came up in #2122 where relative library paths showed up with
backslashes on Windows. It's hard to run acceptance tests where paths
may be in either form. This change updates path translation logic to
always use forward slash-separated paths, including for absolute paths.
## Tests
* Unit tests pass.
* Confirmed that code where library paths are used uses the `filepath`
package for path manipulation. The functions in this package always
normalize their inputs to be platform-native paths.
* Confirmed that code that uses absolute paths works with forward
slash-separated paths on Windows.
## Changes
We perform a check during path translation that the path being
referenced is contained in the bundle's sync root. If it isn't, it's not
a valid remote reference. However, this doesn't apply to paths that are
_always_ local, such as the artifact path. An artifact's build command
is executed in its path. Files created by the artifact build (e.g.
wheels or JARs) don't need to be in the sync root because they have a
dedicated and different upload path into `${workspace.artifact_path}`.
Therefore, this check that a path is contained in the bundle's sync root
doesn't apply to artifact paths. This change modifies the structure of
path translation to allow opting out of this check.
Fixes#1927.
## Tests
* Existing and new tests pass.
* Manually confirmed that building and using a wheel built outside the
sync root path works as expected.
* No acceptance tests because we don't run build as part of validate.
Pieter Noordhuis