doc(examples): update the instructions now that cargo-hf2's issue has been fixed

Author: yvt

examples/basic_wio_terminal/README.md

@@ -2,11 +2,14 @@ This directory contains an example R3 application for [Wio Terminal][1].
 
 Build the application by `cargo build --release`.
 
-See <https://github.com/atsamd-rs/atsamd/blob/master/boards/wio_terminal/examples/README.md#wio-terminal-examples> for how to flash the application. The recommended way is to use [cargo-hf2][2], but you need a version that has [hf2-rs#44][1] merged:
+See <https://github.com/atsamd-rs/atsamd/blob/master/boards/wio_terminal/examples/README.md#wio-terminal-examples> for how to flash the application. The recommended way is to use [cargo-hf2][2] 0.3.3 or later (pre-[hf2-rs#44][1] versions will silently write a corrupted image):
 
 ```shell
-cargo install cargo-hf2 --git https://github.com/yvt/hf2-rs.git --rev 3b0743d0d7fd4005973e6b44f45b391f05336bed
+cargo install cargo-hf2
 cargo hf2 --release --vid 0x2886 --pid 0x002d
 ```
 
+cargo-hf2 might panic upon flashing completion, but it can be ignored safely ([hf2-rs#38][2]).
+
 [1]: https://github.com/jacobrosenthal/hf2-rs/pull/44
+[2]: https://github.com/jacobrosenthal/hf2-rs/issues/38