Add dependency license check to GitHub Actions

[Jonas-Sander]

Check that all packages we use have licenses that we are allowed / we want to use via package:license_checker.

(Unfortunately every new local lib package will have to be added to the licenses_config.yaml manually.)

If it fails the output will list all packages with a non-permitted license.
See this example where I removed the BSD-3-Clause license from permittedLicenses:

 ┌─────────────────────────────────────────────────────────┐
│                             Package Name  License       │
├─────────────────────────────────────────────────────────┤
│                         flutter_markdown  BSD-3-Clause  │
│                              built_value  BSD-3-Clause  │
│                               characters  BSD-3-Clause  │
│                             checked_yaml  BSD-3-Clause  │
│                          cloud_firestore  BSD-3-Clause  │
└─────────────────────────────────────────────────────────┘

Closes #23

[nilsreichardt]

LGTM

(Unfortunately every new local lib package will have to be added to the licenses_config.yaml manually.)

We can later add a command to our CLI that checks if each package we use is mentioned in licenses_config.yaml. This command can then be included in our GitHub checks.

[Jonas-Sander]

LGTM

(Unfortunately every new local lib package will have to be added to the licenses_config.yaml manually.)

We can later add a command to our CLI that checks if each package we use is mentioned in licenses_config.yaml. This command can then be included in our GitHub checks.

This isn't necessary, the pipeline will fail if we don't add it to the file. I just meant that adding it manually still has to be done for each new package (it isn't automated).

[nilsreichardt]

This isn't necessary, the pipeline will fail if we don't add it to the file. I just meant that adding it manually still has to be done for each new package (it isn't automated).

Ah nice, this shouldn't be a big problem 👍