v1.9.0 to add more Timers to SAMD21

### Releases v1.9.0

1. Add TC4, TC5, TCC1 and TCC2 Timers to SAMD21
2. Add example [SAMD21_MultiTimers](examples/SAMD21_MultiTimers) to demo the how to use all 6 SAMD21 timers simultaneously.
3. Add functions `attachInterruptInterval_MS()` and `setInterval_MS()`
4. Rewrite examples to take advantage of new functions and timers

Author: khoih-prog

README.md

@@ -165,7 +165,7 @@ The catch is **your function is now part of an ISR (Interrupt Service Routine),
  7. To use with some examples, depending on which Ethernet card you're using:
    - [`Ethernet_Generic library v2.3.0+`](https://github.com/khoih-prog/Ethernet_Generic) for W5100, W5200 and W5500/WIZ550io/WIZ850io/USR-ES1 with Wiznet W5500 chip.  [![GitHub release](https://img.shields.io/github/release/khoih-prog/Ethernet_Generic.svg)](https://github.com/khoih-prog/Ethernet_Generic/releases/latest)
    - [`EthernetENC library v2.0.2+`](https://github.com/jandrassy/EthernetENC) for ENC28J60. [![GitHub release](https://img.shields.io/github/release/jandrassy/EthernetENC.svg)](https://github.com/jandrassy/EthernetENC/releases/latest). **New and Better**
-   - [`UIPEthernet library v2.0.11+`](https://github.com/UIPEthernet/UIPEthernet) for ENC28J60. [![GitHub release](https://img.shields.io/github/release/UIPEthernet/UIPEthernet.svg)](https://github.com/UIPEthernet/UIPEthernet/releases/latest)
+   - [`UIPEthernet library v2.0.12+`](https://github.com/UIPEthernet/UIPEthernet) for ENC28J60. [![GitHub release](https://img.shields.io/github/release/UIPEthernet/UIPEthernet.svg)](https://github.com/UIPEthernet/UIPEthernet/releases/latest)
  7. To use with some examples
    - [`SimpleTimer library`](https://github.com/jfturcot/SimpleTimer) for [ISR_16_Timers_Array](examples/ISR_16_Timers_Array) and [ISR_16_Timers_Array_Complex](examples/ISR_16_Timers_Array_Complex) examples. New to avoid error with `old` Sparkfun core.