Update changelog.txt

changelog.txt

@@ -4,6 +4,20 @@ Version history:
 ================
 
 
+---
+v.1.3 - 07/05/2018
+(Contributed by Natalia Bondarenko)
+ * Added .gitignore.
+ * Unit tests:
+    - dataset for tests, test cases for ArgumentParser, WordCounter, some functions (positive testing);
+    - added return statement in some functions for testing purposes.
+ * Utils:
+    - transfer functions that do not belong to any class in utils (def get_file_extension and def human_mem_size);
+    - added decorator to intercept KeyboardInterrupt and common Exceptions;
+    - class WordCounter moved to separate file.
+ * To run the main program thread, the function def main_flow(args) was created.
+ * Added some Type hints.
+
 ---
 v.1.2 - 04/05/2018
 (Special thanks to Natalia Bondarenko, Fred Cirera and Sridhar Ratnakumar)