Replace space with dash in tensorflow-sys-runtime keywords

Author: adamcrume

tensorflow-sys-runtime/Cargo.toml

@@ -3,7 +3,7 @@ name = "tensorflow-sys-runtime"
 version = "0.2.0"
 authors = ["Brian Jones <[email protected]>"]
 license = "Apache-2.0"
-keywords = ["TensorFlow", "runtime bindings"]
+keywords = ["TensorFlow", "runtime-bindings"]
 description = "The package provides runtime bindings to TensorFlow."
 documentation = "https://tensorflow.github.io/rust"
 homepage = "https://github.com/tensorflow/rust"