Cargo: Update the sha2 dependency

We need 0.10+ or else we hit that error:

error[E0277]: the trait bound `sha2::Sha256: CoreProxy` is not satisfied
  --> src/blockcipher/aes_ctr.rs:25:22
   |
25 |     pub hmac: Option<HmacSha256>,
   |                      ^^^^^^^^^^ the trait `CoreProxy` is not implemented for `sha2::Sha256`
   |
   = note: required because of the requirements on the impl of `BlockSizeUser` for `HmacCore<sha2::Sha256>`

For more information about this error, try `rustc --explain E0277`.
error: could not compile `ocicrypt-rs` due to previous error

Signed-off-by: Samuel Ortiz <s.ortiz@apple.com>

Cargo.toml

@@ -27,7 +27,7 @@ prost-types = "0.9.0"
 aes-gcm = "0.9.2"
 ctr = ">=0.1"
 rand = ">=0.8"
-sha2 = ">=0.9"
+sha2 = ">=0.10"
 hmac = ">=0.12"
 aes = { version = ">=0.7", features = ["ctr"] }
 base64-serde = "0.6"