Language repositories are going to need .assets added to their respective .gitignore files

When a user executes test-proxy restore -a <pathToAssets.json>\assets.json, by default it'll create an **.assets** directory in the root of the repository. Git status shows this as untracked and it shouldn't be showing up at all.
```
> git status
On branch main
Untracked files:
  (use "git add <file>..." to include in what will be committed)
        .assets/
```
