different label and color while task is running

[tregota]

As suggested in #27 Gave it a shot. Works for me. But I have zero prior experience with the VS Code Extension API.

[sapphyrus]

@actboy168 A little late, but any chance this will get merged?

[actboy168]

see https://github.com/actboy168/vscode-tasks/commit/7ef7e1bab90e65a2bb82e9b6f9bb5be67098977b