Refine "no binary files in source archive" check

[abesto]

Some binary files are actually totally fine, like images, for example. Also seems to mark .json files as binary for some reason. Downgrading to NOTE for now.

[codefromthecrypt]

notably the next zipkin release will include these, which are present in 2.14.0. The other files that are being complained about will be gone

> /tmp/tmppa_5v1dw/unzipped/zipkin-2.14.0/zipkin-lens/src/img/zipkin-logo.svg
> /tmp/tmppa_5v1dw/unzipped/zipkin-2.14.0/zipkin-lens/static/favicon.ico