Update license expression in s3

Author: sgrif

src/s3/Cargo.toml

@@ -3,7 +3,7 @@
 name = "cargo-registry-s3"
 version = "0.2.0"
 authors = ["Alex Crichton <[email protected]>"]
-license = "MIT/Apache-2.0"
+license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/crates.io"
 description = "Interaction between crates.io and S3 for storing crate files"