Update peripheral support in README (#67)

Author: astapleton

README.md

@@ -36,14 +36,15 @@ of support for peripherals is shown in the table below.
 |------------|----|---|---|
 | GPIO       | ✅ | - | |
 | ICache     | ✅ | - | |
-|| I2C        | ✅ | - | |
+| I2C        | ✅ | - | |
 | SPI        | ✅ | - | SPI peripheral only (not implemented for USART peripheral) |
+| DMA        | ✅ | - | Currently one-shot transfers only |
+| USB        | ✅ | - | |
 | CAN        | 🚧 | - | |
 | Rng        | 🚧 | [#34](https://github.com/stm32-rs/stm32h5xx-hal/issues/34)| |
 | UART       | 🚧 | - | |
-| DMA        | 🚧 | - | |
+| Timers     | 🚧 | - | |
 | ADC        | ❌ | [#35](https://github.com/stm32-rs/stm32h5xx-hal/issues/35) | |
-| Timers     | ❌ | - | |
 | PWM        | ❌ | - | |
 | Rtc        | ❌ | - | |
 | Flash      | ❌ | - | |