[bug-fix] Cherry-pick remove extra period to Release 10 (#4680)

* Remove extra period

* Update changelog

* Re add a period (#4676)

* Adding a trailing period

* formating

Co-authored-by: Vincent-Pierre BERGES <vincentpierre@unity3d.com>

Co-authored-by: Vincent-Pierre BERGES <vincentpierre@unity3d.com>

com.unity.ml-agents/CHANGELOG.md

 - Fixed an issue where runs could not be resumed when using TensorFlow and Ghost Training. (#4593)
 - Change the tensor type of step count from int32 to int64 to address the overflow issue when step
 goes larger than 2^31. Previous Tensorflow checkpoints will become incompatible and cannot be loaded. (#4607)
+ - Remove extra period after "Training" in console log. (#4674)
 
 
 ## [1.5.0-preview] - 2020-10-14

ml-agents/mlagents/trainers/stats.py

     def write_stats(
         self, category: str, values: Dict[str, StatsSummary], step: int
     ) -> None:
-        is_training = "Not Training."
+        is_training = "Not Training"
-                is_training = "Training."
+                is_training = "Training"
 
         elapsed_time = time.time() - self.training_start_time
         log_info: List[str] = [category]
         else:
             log_info.append("No episode was completed since last summary")
             log_info.append(is_training)
-        logger.info(". ".join(log_info))
+        logger.info(". ".join(log_info) + ".")
 
     def add_property(
         self, category: str, property_type: StatsPropertyType, value: Any