Chinese (Simplified) translation update

Contributor states "I spent two days in my spare time translating,
amateur+machine translation, I don't know whether it meets the
requirements."

I reviewed a handful of them (using Google Translate) and they
appear alright to me, but it'd be beneficial to have a native
speaker take a pass at this.  (The previous update appears to have
been 2017, FWIW.)

docs/AUTHORS.txt

@@ -6,7 +6,7 @@ Copyright (c) 2002-2023
 Various contributors (see below, and CHANGES.txt)
 https://tuxpaint.org/
 
-June 17, 2002 - March 29, 2023
+June 17, 2002 - April 8, 2023
 
 * Design and Coding:
 
@@ -662,6 +662,7 @@ June 17, 2002 - March 29, 2023
     Huang Zuzhen <zuzhenhuang@vip.sina.com>
     Wang Jian
     Never Min <nevermin@gmail.com>
+    臧传明 <qdeduos@163.com>
 
   * Chinese (Simplified) README and FAQ documentation
     HackerGene <hackergene@gmail.com>

docs/CHANGES.txt

@@ -6,9 +6,12 @@ Copyright (c) 2002-2023
 Various contributors (see below, and AUTHORS.txt)
 https://tuxpaint.org/
 
-2023.April.3 (0.9.30)
+2023.April.8 (0.9.30)
   * Localization Updates:
     ---------------------
+    * Chinese (Simplified) translation
+      臧传明 <qdeduos@163.com>
+
     * French translation
       Jacques Chion <jacques.chion@orange.fr>