docs: remove signature requirement from CONTRIBUTING.md (HDFGroup#2784)

Per 2023-04-14 engineering team meeting decision

CONTRIBUTING.md

@@ -94,7 +94,6 @@ The release note entry syntax is shown below.
 
       Problem/Solution
 
-      Signature
 ```
 
 * **Entry Elements** - The elements of the entry - title, problem, solution, and signature - are described in more detail in the table
@@ -112,10 +111,6 @@ You might also consider the following as you describe the solution:
         * What is the functional impact?
         * Is there a workaround – a way for users design their software so as not to encounter the issue? If so, what is the workaround?
         * For a performance fix, how has the performance improved? Links to published documentation would be good.
-    * **Signature** - Each entry must be signed with the initials of the author, the date in YYYY/MM/DD format, and the JIRA ticket number. The
-following is an example entry written by developer Xavier Zolo on April 16, 2014 about JIRA ticket HDFFV-5555: (XYZ - 2014/04/16, HDFFV-5555). The
-signature is enclosed in parentheses. JIRA or Github numbers should not be used in the description of the problem or the solution. They are like
-abbreviations that customers and external users will not be able to interpret.
 
 # Checklist <A NAME="checklist"></A>