fix: include /test/ folder in tsconfig.json

[erickzhao]

Our various test folders are called /test/, but #80 called them /tests/ instead.

[erickzhao]

Build is failing.

So the build seems to be passing with this commit reverted, and if include is just "include": ["src/**/*"].

However, when the build passes, I get these lint errors when looking at a test file:

Parsing error: "parserOptions.project" has been set for @typescript-eslint/parser.
The file does not match your project config: modules/bot/test/github-client.spec.ts.
The file must be included in at least one of the projects provided

[erickzhao]

Since this PR doesn't solve the core issue, I'm going to close it and track the problem in #92.