local crate without license: failed to parse synthesized license expression

[kamulos]

Describe the bug
Having a local crate without a license used to work without a problem. Now with the newest version of cargo-about I get an error and cannot find any information in the documentation about it.

The error is:

error: failed to parse synthesized license expression
  ┌─ xyz 0.1.0.license:1:1
  │
1 │
  │ ^ empty expression

To Reproduce
Steps to reproduce the behavior:

1. Create a new project with cargo new xyz
2. Copy the default about.hbs file
3. Run cargo about generate about.hbs with the newest version of cargo-about

Expected behavior
It should not break the (until now) flawlessly working CI. Alternatively there should be documentation how to solve this.

[Jake-Shadle]

You can workaround this by adding a LicenseRef-<some_name> for now, but I'll need to add a config that can just ignore local crates that don't have a stated license.

[Jake-Shadle]

More details on the custom SPDX identifiers is here https://embarkstudios.github.io/cargo-deny/checks/licenses/cfg.html#spdx-identifiers