VSCode - settings.json

 

{
    "workbench.startupEditor": "none",
    "[go]": {
        "editor.insertSpaces": true,
        "editor.formatOnSave": false
    },
    "editor.fontSize": 16,
    "terminal.integrated.fontSize": 16,
    "go.toolsManagement.autoUpdate": true,
    "go.testFlags": [
        "-count=1",
        "-v"
    ],
    "go.useLanguageServer": false
}

 

Disabling the language server can prevent it from automatically formatting the file on save, so the indent spaces won't be replaces with tabs.