Functions emulator does not allow directories with a period as a

### [REQUIRED] Environment info
firebase-tools: 9.20.0

Platform: macOS

### [REQUIRED] Test case
Create a project folder with a period, e.g. ".firebaseProject/functions" and run emulator.

### [REQUIRED] Steps to reproduce
This regex /(^|[\/\\])\../ excludes not only files with a period, it also excludes directories.

https://github.com/firebase/firebase-tools/blob/817c261a0a5c68b0ce96137a578a1d5b5ffa90f9/src/emulator/functionsEmulator.ts#L385-L392

### [REQUIRED] Expected behavior
Only files with a period should be excluded with chokidar. Changes in my sample project ".firebaseProject/functions" folder should be updated.

### [REQUIRED] Actual behavior
Changes in functions folder are not updated, because directories with a period are excluded.