migration-guides: use contributor real name

From the "Signed-off-by" information from his commits

(From yocto-docs rev: 7a2416b8d920f2af6d98df7aeb10d51268a15cd6)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/migration-guides/release-notes-3.4.2.rst

@@ -167,7 +167,7 @@ Contributors to 3.4.2
 -  Vyacheslav Yurkov
 -  Yongxin Liu
 -  pgowda
--  wangmy
+-  Wang Mingyu
 
 Repositories / Downloads for 3.4.2
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

documentation/migration-guides/release-notes-3.4.3.rst

@@ -124,7 +124,7 @@ Contributors to 3.4.3
 -  Tean Cunningham
 -  Zoltán Böszörményi
 -  pgowda
--  wangmy
+-  Wang Mingyu
 
 Repositories / Downloads for 3.4.3
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

documentation/migration-guides/release-notes-3.4.4.rst

@@ -81,7 +81,7 @@ Contributors to 3.4.4
 -  Richard Purdie
 -  Ross Burton
 -  Tim Orling
--  wangmy
+-  Wang Mingyu
 -  zhengruoqin
 
 Repositories / Downloads for 3.4.4

documentation/migration-guides/release-notes-4.0.1.rst

@@ -174,7 +174,7 @@ Contributors to 4.0.1
 -  Ross Burton
 -  Russ Dill
 -  Steve Sakoman
--  wangmy
+-  Wang Mingyu
 -  zhengruoqin
 
 Repositories / Downloads for 4.0.1

documentation/migration-guides/release-notes-4.0.2.rst

@@ -223,7 +223,7 @@ Contributors to Yocto-4.0.2
 -  Xiaobing Luo
 -  Yi Zhao
 -  leimaohui
--  wangmy
+-  Wang Mingyu
 
 Repositories / Downloads for Yocto-4.0.2
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

documentation/migration-guides/release-notes-4.0.3.rst

@@ -239,7 +239,7 @@ Contributors to Yocto-4.0.3
 -  Yue Tao
 -  gr embeter
 -  leimaohui
--  wangmy
+-  Wang Mingyu
 
 
 Repositories / Downloads for Yocto-4.0.3

documentation/migration-guides/release-notes-4.0.4.rst

@@ -226,7 +226,7 @@ Contributors to Yocto-4.0.4
 -  Yongxin Liu
 -  ghassaneben
 -  pgowda
--  wangmy
+-  Wang Mingyu
 
 Repositories / Downloads for Yocto-4.0.4
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~