docs(contributing): lower commit message length

See https://github.com/blog/926-shiny-new-commit-styles on the reason
behind this change. A commit message body longer than 72 characters is
wrapped.

Author: Matthew Fisher

CONTRIBUTING.md

@@ -64,8 +64,8 @@ letter in a paragraph must be capitalized.
 All breaking changes need to be mentioned in the {footer} with the description of the
 change, the justification behind the change and any migration notes required.
 
-Any line of the commit message cannot be longer than 90 characters, with the subject line
-limited to 70 characters. This allows the message to be easier to read on github as well
+Any line of the commit message cannot be longer than 72 characters, with the subject line
+limited to 50 characters. This allows the message to be easier to read on github as well
 as in various git tools.
 
 The allowed {types} are as follows:

docs/contributing/standards.rst

@@ -194,8 +194,8 @@ Format of the Commit Message
     <BLANK LINE>
     {footer}
 
-Any line of the commit message cannot be longer than 90 characters, with the subject
-line limited to 70 characters. This allows the message to be easier to read on github
+Any line of the commit message cannot be longer than 72 characters, with the subject
+line limited to 50 characters. This allows the message to be easier to read on github
 as well as in various git tools.
 
 Subject Line