Bump Microsoft.NET.Test.Sdk from 18.5.1 to 18.6.0 - #190

Bad credentials HttpError: Bad credentials at /action/node_modules/@octokit/request/dist-node/index.js:86:21 at process.processTicksAndRejections (node:internal/process/task_queues:95:5) at async approve (file:///action/lib/api.js:2:3) at async default (file:///action/lib/index.js:33:5) at async file:///action/index.js:53:1