Update GitHub workflow action for automated VSCode marketplace publishing

[Ismoh]

There is already some workaround/preparations, but I don't like it a lot.
action
custom local VSCode task

I prefer GitHub workflow action to do everything, which is necessary, but we first need to make a decision on #11

[sewbacca]

Yeah it would probably be best if building is done by CI.
I find it weird, that the compiled .js, .map files and the lldebugger.lua file are all in the code tree, as they should always be generated from the source files anyways. The only upside I can see is referencing Lua transpiled code in issues, since that is, what people will see, wenn something goes horribly wrong. However I believe this is what has lead the perfectly reasonable PR #10 being merged into a a null version with no new content being published.

On a tangental note: I probably messed up v0.3.8: I was trying to get comfortable with publishing, but I had to do lot of force pushing back and forth. I tested the release, and my fixes seem to went through anyways. However I am not sure if your merge has been correctly published. Do you want to manually reupload v0.3.8 or do we just wait until the next version?