Add matching brackets implementation for U6

u6/matching-brackets.py

@@ -0,0 +1,12 @@
+def is_paired(input_string):
+    spisok = []
+    slovnik = {')': '(', ']': '[', '}': '{'}
+    
+    for gnx in input_string:
+        if gnx in "([{":
+            spisok.append(gnx)
+        elif gnx in ")]}":
+            if not spisok or spisok[-1] != slovnik[gnx]:
+                return False
+            spisok.pop()
+