Ease debugging, fix some CI issues, tweak folder structure (#200)

* Enable debug for OTP versions' listings

* Make it easier to detect

* Prevent error annotation on expected error

The fact that one mirror fails in the above test and others follow
working is test enough for me

A single failing mirror should fail, but it's confusing to have
an error annotation for a success (via continue-on-error) while
not being able to suppress it via GitHub Actions

* Trying to figure out why we have a rebar_core exception

Might simply be that the bug is already fixed and we need to bump rebar3

* Try to debug into non-JSON input

* Prevent error in rebar_core

We're getting Access Denied for
Fetching registry from "https://repo.hex.pm:443/registry.ets.gz?"

* Try to figure out what's breaking tests

* Make jsonParse(...).map failure more understandable

* Ease test maintenance

* Tweak folder structure while moving console._ to core._

package-lock.json

@@ -9,7 +9,7 @@
       "dependencies": {
         "@actions/core": "1.10.0",
         "@actions/exec": "1.1.1",
-        "@actions/http-client": "^2.1.0",
+        "@actions/http-client": "2.1.0",
         "semver": "7.3.8"
       },
       "devDependencies": {