style: increase git commit title max length to 72

The team found the previous limit of 50 prevents us from making clear
commit summaries.

Signed-off-by: Pablo Barbáchano <pablob@amazon.com>

Author: pb8o

.gitlint

@@ -1,5 +1,5 @@
 [title-max-length]
-line-length=50
+line-length=72
 
 [body-max-line-length]
 line-length=72