auto detection of virtual env in vs-code workspsce

**Is your feature request related to a problem? Please describe.**
As a beginner, it is difficult to set virtual env that works with code-runner and its stress when inter-switching multiple virtual env for a project as you have to update the python path in the executor map settings.

**Describe the solution you'd like**
I think it will be fine to automatically detect the current virtual env in the workspace and update when there is a switch in virtual env; that is to let there be a trigger in code-runner that will always carry out such operations.