README: stress right Cargo.toml, add branch to git instructions
## Basic usage
-1. Start from the [`app-template`] then add this test to the dependencies of the `testsuite` crate
+0. If you don't have a project setup yet, start from the [`app-template`]
+
[`app-template`]: https://github.com/knurling-rs/app-template
+1. In the **testsuite** crate, add `defmt-test` to the dependencies:
+
``` toml
# testsuite/Cargo.toml
-[dependencies]
-defmt-test = { git = "https://github.com/knurling-rs/defmt-test" }
+[dependencies.defmt-test]
+git = "https://github.com/knurling-rs/defmt-test"
+branch = "main"
```
2. Within the `testsuite/tests/test.rs` file, create a `tests` module and mark it with the `#[defmt_test::tests]` attribute. Within that module write `std`-like unit tests: functions marked with the `#[test]` attribute.
