Update version of TaskInfo header serialization after backport

Update the serialization version after backporting #27764 to 6.x.

Author: imotov

server/src/main/java/org/elasticsearch/tasks/TaskInfo.java

@@ -97,7 +97,7 @@ public TaskInfo(StreamInput in) throws IOException {
         runningTimeNanos = in.readLong();
         cancellable = in.readBoolean();
         parentTaskId = TaskId.readFromStream(in);
-        if (in.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (in.getVersion().onOrAfter(Version.V_6_2_0)) {
             headers = in.readMap(StreamInput::readString, StreamInput::readString);
         } else {
             headers = Collections.emptyMap();
@@ -115,7 +115,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeLong(runningTimeNanos);
         out.writeBoolean(cancellable);
         parentTaskId.writeTo(out);
-        if (out.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (out.getVersion().onOrAfter(Version.V_6_2_0)) {
             out.writeMap(headers, StreamOutput::writeString, StreamOutput::writeString);
         }
     }