use pinned dependencies for RCs

otherwise cargo will update to newer RCs which will break the build.
the update to 1.0.0-rc.2 will come in a follow-up commit (a new release
of `stm32f4xx-hal` is needed to ensure that the example builds).

Author: rursprung

Cargo.toml

@@ -11,9 +11,9 @@ keywords = ["tb6612fng", "driver", "motor", "controller", "embedded-hal-driver"]
 license = "MIT OR Apache-2.0"
 
 [dependencies]
-embedded-hal = "1.0.0-rc.1"
+embedded-hal = "=1.0.0-rc.1"
 
 defmt = { version = "0.3", optional = true }
 
 [dev-dependencies]
-embedded-hal-mock = { version = "0.10.0-rc.2", features = ["eh1"] }
+embedded-hal-mock = { version = "=0.10.0-rc.2", features = ["eh1"] }