Update go-sqlcmd to v0.12.0

[shueybubbles]

This version fixes several issues with batch parsing and variables

[zijchen]

@shueybubbles Could you run npm run build and commit the main.js changes too? main.js is where the action actually runs out of so every time we change the ts files we need to build and update main.js

[shueybubbles]

I was hoping to complete this PR completely within the github UI and not pull down bits locally :-)
Are the pre-reqs to build very complex to install?

[shueybubbles]

maybe consider moving the version number out of the typescript into some config file that main.js reads so it's resilient to minor changes

[zijchen]

I was hoping to complete this PR completely within the github UI and not pull down bits locally :-) Are the pre-reqs to build very complex to install?

You just need to have npm installed, then run npm install and npm run build from the root :)

[zijchen]

maybe consider moving the version number out of the typescript into some config file that main.js reads so it's resilient to minor changes

That's a good idea, I added #164 to track