Reproduction steps:
1. Create a new Project
2. Set external editor to VS Code (Edit -> Preferences -> External Tools -> External Script Editor -> Visual Studio Code)
3. Create a new C# Script in the project.
4. Open C# Project (Assets -> Open C# Project)
5. Open the "Assembly-CSharp.csproj" file in VSCode
6. Inspect the <LangVersion> XML tag

Expected result: Unity generates the <LangVersion> Tag with the latest C# language version supported by the target framework set in project settings. (i.e. 8.0)
Actual result: Unity generates 'latest' in the <LangVersion> Tag

Reproducible with: 1.2.2, 1.2.3 (2019.4.32f1, 2020.3.23f1), 1.2.4 (2019.4.32f1, 2020.3.23f1, 2021.1.28f1, 2021.2.3f1, 2022.1.0a15)