Shebang Fix (#1477)

* Shebang Fix

Per George's "I'd merge a PR replacing the 4 python3.7 with python3" on Discord. George updated Python to 3.8.2 for webcam tools, which broke manager from launching. Instead of chasing the exact version, it seems more reasonable to fall back to 3.

* More Python3.7's

scripts/get_fan_control_type.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3.7
+#!/usr/bin/env python3
 import os
 from smbus2 import SMBus
 

selfdrive/athena/athenad.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3.7
+#!/usr/bin/env python3
 import json
 import os
 import hashlib

selfdrive/manager.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3.7
+#!/usr/bin/env python3
 import os
 import time
 import sys

selfdrive/thermald/thermald.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3.7
+#!/usr/bin/env python3
 import os
 import json
 import copy