Add apk to supported package managers

What does this MR do and why?

This MR adds apk to the list of known package managers enum in GraphQL.

Related to #458295

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Make sure you have a working CI registry.
2. Create a project with a Dockerfile and .gitlab-ci.yml
3. Run the build process
4. Use the GraphQL query below, it shouldn't error out

Dockerfile

FROM alpine:latest
RUN apk add --no-cache p11-kit=0.25.3-r0 libpng=1.6.40-r0 fontconfig=2.14.2-r4

.gitlab-ci.yml

include:
  - template: Jobs/Build.gitlab-ci.yml
  - template: Jobs/Container-Scanning.gitlab-ci.yml

container_scanning:
  variables:
    CS_DEFAULT_BRANCH_IMAGE: $CI_REGISTRY_IMAGE/$CI_DEFAULT_BRANCH:$CI_COMMIT_SHA

GraphQL

{
  project(fullPath: "<path to project>") {
    dependencies(after: "") {
      pageInfo {
        endCursor
        startCursor
        hasNextPage
      }
      nodes {
        name
        version
        packager
        location {
          path
          blobPath
        }
        licenses {
          name
          url
        }
      }
    }
  }
}