installation fails during `go get`

[atz]

Can't seem to install anderson presently, using the documented step:

# go get -u github.com/contraband/anderson 
go get: installing executables with 'go get' in module mode is deprecated.
	To adjust and download dependencies of the current module, use 'go get -d'.
	To install using requirements of the current module, use 'go install'.
	To install ignoring the current module, use 'go install' with a version,
	like 'go install example.com/cmd@latest'.
	For more information, see https://golang.org/doc/go-get-install-deprecation
	or run 'go help get' or 'go help install'.
# github.com/contraband/anderson/anderson
../../go/pkg/mod/github.com/contraband/anderson@v0.0.0-20181021050616-f8ddaba3211d/anderson/classifier.go:41:3: invalid case license.ErrNoLicenseFile in switch on err.Error() (mismatched types error and string)
../../go/pkg/mod/github.com/contraband/anderson@v0.0.0-20181021050616-f8ddaba3211d/anderson/classifier.go:47:3: invalid case license.ErrUnrecognizedLicense in switch on err.Error() (mismatched types error and string)

The erroring lines correspond to these:
https://github.com/contraband/anderson/blob/master/anderson/classifier.go#L40-L47

This is on an M1 Macbook:

go version
go version go1.17.8 darwin/amd64