Support X-Gitlab-Content-Sha256 header (#904)

src/main/java/org/gitlab4j/api/RepositoryFileApi.java

@@ -71,6 +71,7 @@ public class RepositoryFileApi extends AbstractApi {
         RepositoryFile file = new RepositoryFile();
         file.setBlobId(response.getHeaderString("X-Gitlab-Blob-Id"));
         file.setCommitId(response.getHeaderString("X-Gitlab-Commit-Id"));
+        file.setContentSha256(response.getHeaderString("X-Gitlab-Content-Sha256"));
 
         String encoding = response.getHeaderString("X-Gitlab-Encoding");
         file.setEncoding(Constants.Encoding.forValue(encoding));
@@ -515,4 +516,4 @@ public class RepositoryFileApi extends AbstractApi {
     public Stream<Blame> getBlameStream(Object projectIdOrPath, String filePath, String ref) throws GitLabApiException {
        return (getBlame(projectIdOrPath, filePath, ref, getDefaultPerPage()).stream());
     }
-}
\ No newline at end of file
+}