Fix PowerShell command echoing issues

Merged username-removed-204177 requested to merge SPARTAN563/gitlab-ci-multi-runner:master into master

When running PowerShell commands which contain the " character, the current echo functionality (which naively doesn't escape those characters) will result in broken build scripts. This MR addresses that issue by explicitly escaping those characters when echoing commands in PowerShell.

Before

echo ".\build.ps1 "main.go""
.\build.ps1 "main.go"

After

echo ".\build.ps1 `"main.go`""
.\build.ps1 "main.go"