Filtering providers using the --provider-name option seems to result in no providers being selected

[westonsteimel]

Please provide a set of steps on how to reproduce the issue

grype-db build --provider-name alpine
[0000]  INFO grype-db version: 0.19.1
[0000]  INFO building database build-directory=./build providers=[] schema=5
[0000]  INFO database created path=build/vulnerability.db

What happened:

Passing any --provider-name flags seems to result in no providers being selected and therefore results in an empty database being built.

What you expected to happen:

grype-db build --provider-name alpine
[0000]  INFO grype-db version: 0.19.1
[0000]  INFO building database build-directory=./build providers=[alpine] schema=5
[0000]  INFO database created path=build/vulnerability.db

Anything else we need to know?:

I could have sworn I've used this before, but it seems not to work correctly in any release I've tried so far

Environment:

• Output of grype-db version:

Application:        grype-db
Version:            0.19.1
BuildDate:          2023-08-25T15:39:14Z
GitCommit:          500c18af007c3899498560d576c9650ace5f5b8d
GitDescription:     v0.19.1
Platform:           darwin/arm64
GoVersion:          go1.20.7
Compiler:           gc

• OS (e.g: cat /etc/os-release or similar):

[westonsteimel]

Ah, I forgot to add -g, so it wasn't generating a vunnel config

grype-db build --provider-name alpine -g works as expected

grype-db --provider-name github build -g
[0000]  INFO grype-db version: 0.19.1
[0001]  INFO building database build-directory=./build providers=[github] schema=5
[0005]  INFO database created path=build/vulnerability.db