chore: configure eslint vs code plugin (#423)

Summary:

The .eslintrc.yaml is located in site, rather than the root of the
repository. The VS Code plugin has a CWD of the repository root, so it
looks for tsconfig.test.json in the root rather in site.

See Also:

- microsoft/vscode-eslint#196
- typescript-eslint/typescript-eslint#251

.vscode/settings.json

@@ -75,5 +75,6 @@
     "webrtc",
     "xerrors",
     "yamux"
-  ]
+  ],
+  "eslint.workingDirectories": ["./site"]
 }

site/.eslintrc.yaml

@@ -17,11 +17,12 @@ extends:
 parser: "@typescript-eslint/parser"
 parserOptions:
   ecmaVersion: 2018
-  project:
-    - "./tsconfig.test.json"
+  project: "./tsconfig.test.json"
   sourceType: module
   ecmaFeatures:
     jsx: true
+  # REMARK(Grey): We might want to move this to repository root eventually to
+  #               lint multiple projects (supply array to project property).
   tsconfigRootDir: "./"
 plugins:
   - "@typescript-eslint"