Update cortex-m-rt on crates.io to include skip-data-copy feature

The skip-data-copy feature was added in commit [6f0414c](https://github.com/rust-embedded/cortex-m/commit/6f0414c95a21f713278531e56861cbfa7aae0e55) and is not included in the latest release on crates.io. Could a new release be cut to make this feature available?
