v1.0.0 for hardware-PWM on megaAVR boards

### Initial Releases v1.0.0

1. Initial coding to support **megaAVR boards, such as UNO WiFi Rev2, AVR_Nano_Every, etc.**, using `Arduino megaAVR` or `MegaCoreX` core
2. The hardware-based PWM channels using TimerB can generate very high frequencies.

README.md

@@ -156,7 +156,7 @@ Another way to install is to:
 
 TCB0-TCB3 are 16-bit timers.
 
-### 5. Important Notes
+### 3. Important Notes
 
 Before using any Timer, you have to make sure the **Timer has not been used by any other purpose.**