Fixing print of lint errors in golangci-lint action

[patrickhuie19]

Previously the lint artifact was in xml, so the step to find errors omits the file name when logging to the action. This means that devs still have to pull the artifact down locally to fix lint errors, which I think is exactly what the step was trying to prevent.

Example:
https://github.com/smartcontractkit/chainlink-relay/actions/runs/6896336069/job/18762232176?pr=248

I saw two paths forward:

• Change the output encoding to json, which is easier to parse than xml
• Write a more complex parser for the xml to include the file name with the error

I chose the first, with the caveat that golangci-lint allows multiple output encodings/files, which is necessary as sonar only allows for golangci-lint artifacts with the checkstyle format: https://docs.sonarsource.com/sonarqube/latest/analyzing-source-code/importing-external-issues/external-analyzer-reports/#list-of-properties

The main thing we have to make sure of here is that no integration with sonar is broken.
Verified with https://github.com/smartcontractkit/chainlink-relay/pull/246/checks?check_run_id=18763287499 on commit 3328779 of this PR, which has parity with the same lint errors on #248