Add timestamp to bundle and validate

Signed-off-by: Aaron Lew <64337293+aaronlew02@users.noreply.github.com>

Author: aaronlew02

sigstore-java/src/test/java/dev/sigstore/timestamp/client/TimestampVerifierTest.java

@@ -22,7 +22,6 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.google.common.io.Resources;
-import com.google.protobuf.util.JsonFormat;
 import dev.sigstore.json.ProtoJson;
 import dev.sigstore.proto.trustroot.v1.TrustedRoot;
 import dev.sigstore.trustroot.SigstoreTrustedRoot;
@@ -46,7 +45,6 @@ public class TimestampVerifierTest {
 
   @BeforeAll
   public static void loadResources() throws Exception {
-
     artifact = "test\n".getBytes(StandardCharsets.UTF_8);
 
     try (var is =
@@ -107,8 +105,9 @@ public static void initTrustRoot() throws Exception {
             Resources.getResource("dev/sigstore/trustroot/staging_trusted_root_with_one_tsa.json"),
             StandardCharsets.UTF_8);
     builder = TrustedRoot.newBuilder();
-    JsonFormat.parser().merge(json, builder);
+    ProtoJson.parser().merge(json, builder);
 
+    trustedRootWithOneTsa = SigstoreTrustedRoot.from(builder.build());
     trustedRootWithOneTsa = SigstoreTrustedRoot.from(builder.build());
 
     json =
@@ -120,6 +119,7 @@ public static void initTrustRoot() throws Exception {
     ProtoJson.parser().merge(json, builder);
 
     trustedRootWithOutdatedTsa = SigstoreTrustedRoot.from(builder.build());
+    trustedRootWithOutdatedTsa = SigstoreTrustedRoot.from(builder.build());
   }
 
   @Test