Upgrade deps

Summary:
Couldn't do this because we were stuck on an old version
of digest internally with breaking changes. Now there's a
`sha2-9` option to make it build.

Reviewed By: mweststrate

Differential Revision: D26404582

fbshipit-source-id: 9851de3439ea263eaddb558daaf4cf9e73b062cc

packer/src/main.rs

@@ -105,7 +105,6 @@ fn pack_platform(
 ) -> Result<()> {
     let base_dir = match platform {
         Platform::Mac => path::Path::new(dist_dir).join("mac"),
-        // TODO: Verify this.
         Platform::Linux => path::Path::new(dist_dir).join("linux-unpacked"),
         Platform::Windows => path::Path::new(dist_dir).join("win-unpacked"),
     };
@@ -133,7 +132,7 @@ fn sha256_digest<R: io::Read>(mut reader: &mut R) -> Result<HashSum> {
 
     let mut sha256 = Sha256::new();
     std::io::copy(&mut reader, &mut sha256)?;
-    let hash = sha256.result();
+    let hash = sha256.finalize();
 
     Ok(HashSum(data_encoding::HEXLOWER.encode(&hash)))
 }