Adds USR2 changes

Changes.md

@@ -1,3 +1,13 @@
+2.17.5
+-----------
+
+- A `USR2` signal will now reopen _all_ logs, using IO#reopen. Thus, instead of creating a new Logger object, 
+  Sidekiq will now just update the existing Logger's file descriptor [#1163].
+  Like Unicorn, a File object is considered a log file if:
+    - opened with the `O_APPEND` and `O_WRONLY` flags
+    - the current open file handle does not match its original open path
+    - unbuffered (as far as userspace buffering goes, not `O_SYNC`)
+
 2.17.4
 -----------