removed unused import

Author: Anirav Kareddy

src/main/java/software/amazon/encryption/s3/internal/ContentMetadataEncodingStrategy.java

@@ -3,7 +3,6 @@
 import software.amazon.awssdk.protocols.jsoncore.JsonWriter;
 import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
 import software.amazon.awssdk.services.s3.model.PutObjectRequest;
-import software.amazon.awssdk.services.s3.model.S3Request;
 import software.amazon.encryption.s3.S3EncryptionClientException;
 import software.amazon.encryption.s3.materials.EncryptedDataKey;
 import software.amazon.encryption.s3.materials.EncryptionMaterials;