bump dependencies for embassy-net, embassy-time, embassy-futures, and… (#24)

* bump dependencies for embassy-net, embassy-time, embassy-futures, and log; update serde and serde_json versions

* qemu hints added to readme

Author: psytraxx

.gitignore

@@ -16,3 +16,4 @@ target/
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 .idea/
 .env
+image.bin