Release build in VS Code

Edit the tasks.json like this:

{
    "version": "2.0.0",
    "tasks": [
        {
            "taskName": "build Debug",
            "command": "dotnet",
            "type": "process",
            "args": [
                "build",
                "${workspaceFolder}/dotnetcore-test.csproj"
            ],
            "problemMatcher": "$msCompile"
        },
        {
            "taskName": "build Release",
            "command": "dotnet",
            "type": "process",
            "args": [
                "build",
                "${workspaceFolder}/dotnetcore-test.csproj",
                "-c",
                "Release"
            ],
            "problemMatcher": "$msCompile"
        }        
    ]
}

then when you press Ctrl+Shift+B the Command Palette will let you choose between Build Release and Build Debug

source:
https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-build?tabs=netcore2x