Improve output in error cases

[Falco20019]

Right now I occassionally get the following error:

> Run DependencyTrack/gh-upload-sbom@v3
  with:
    serverHostname: xxx.xxx.xxx.xxx
    port: 8443
    apiKey: ***
    projectName: xxx
    projectVersion: develop
    bomFilename: sbom.json
    parent: xxx-xxx-xxx-xxx
    autoCreate: true
    protocol: https
  env:
    NODE_TLS_REJECT_UNAUTHORIZED: 0
Reading BOM: sbom.json...
Uploading to Dependency-Track server xxx.xxx.xxx.xxx...
(node:7862) Warning: Setting the NODE_TLS_REJECT_UNAUTHORIZED environment variable to '0' makes TLS connections and HTTPS requests insecure by disabling certificate verification.
(Use `node --trace-warnings ...` to show where the warning was created)
Error: fetch failed

Sadly the Error: fetch failed is not really helping to find out what's going wrong. Re-running the job usually fixes it. It's not a firewall issue, since we had that before and that showed as a timeout instead of fetching failing.

This is because core.setFailed(error.message); is only logging the message part of error (which isn't useful). Either log the full error or at least include the error.cause.