Fix debian/changelog format for 2.7.1 entry

The 2.7.1 entry had two problems:

- The date was on the same line as the header (after urgency=medium),
  which violates deb-changelog(5) and triggered "bad key-value after ';'".
- The 2.7.1 block had no trailer line ( -- Maintainer Date), so the
  parser hit the next entry and reported "found start of entry where expected more change data or trailer".

Correct format: header line contains only "package (version) dist;
urgency=urgency", then change lines, then a blank line, then the
trailer " -- Name <email>  Day, DD Mon YYYY HH:MM:SS +ZZZZ".

Author: mjnowen

debian/changelog

@@ -1,7 +1,9 @@
-amazon-ec2-net-utils (2.7.1) unstable; urgency=medium Fri, 19 Sep 2025 22:46:33 +0000
+amazon-ec2-net-utils (2.7.1) unstable; urgency=medium
 
   * New upstream release 2.7.1
 
+ -- Joe Kurokawa <joekurok@amazon.com>  Fri, 19 Sep 2025 22:46:33 +0000
+
 amazon-ec2-net-utils (2.7.0) unstable; urgency=medium
 
   * New upstream release 2.7.0