Fix deprecated as_slice() calls in aws-smithy-checksums

Replace deprecated as_slice() method calls with as_ref() to resolve
deprecation warnings from generic-array upgrade. This affects SHA1,
SHA256, and MD5 checksum implementations.

Fixes compilation warnings:
- error: use of deprecated method GenericArray::as_slice
- help: please upgrade to generic-array 1.x

Bumps version from 0.63.9 to 0.63.10.

Author: rcoh

rust-runtime/aws-smithy-checksums/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "aws-smithy-checksums"
-version = "0.63.9"
+version = "0.63.10"
 authors = [
     "AWS Rust SDK Team <aws-sdk-rust@amazon.com>",
     "Zelda Hessler <zhessler@amazon.com>",

rust-runtime/aws-smithy-checksums/src/lib.rs

@@ -266,7 +266,7 @@ impl Sha1 {
 
     fn finalize(self) -> Bytes {
         use sha1::Digest;
-        Bytes::copy_from_slice(self.hasher.finalize().as_slice())
+        Bytes::copy_from_slice(self.hasher.finalize().as_ref())
     }
 
     // Size of the checksum in bytes
@@ -302,7 +302,7 @@ impl Sha256 {
 
     fn finalize(self) -> Bytes {
         use sha2::Digest;
-        Bytes::copy_from_slice(self.hasher.finalize().as_slice())
+        Bytes::copy_from_slice(self.hasher.finalize().as_ref())
     }
 
     // Size of the checksum in bytes
@@ -340,7 +340,7 @@ impl Md5 {
     #[warn(dead_code)]
     fn finalize(self) -> Bytes {
         use md5::Digest;
-        Bytes::copy_from_slice(self.hasher.finalize().as_slice())
+        Bytes::copy_from_slice(self.hasher.finalize().as_ref())
     }
 
     // Size of the checksum in bytes