chore: update maintainer list: Junjie Gao retired (#46)

Signed-off-by: Junjie Gao <junjiegao@microsoft.com>

CODEOWNERS

@@ -1,3 +1,3 @@
 # Repo-Level Owners (in alphabetical order)
 # Note: This is only for the notaryproject/tspclient-go repo
-* @gokarnm @JeyJeyGao @niazfk @priteshbandi @shizhMSFT @toddysm @Two-Hearts @vaninrao10 @yizha1
+* @gokarnm @niazfk @priteshbandi @shizhMSFT @toddysm @Two-Hearts @vaninrao10 @yizha1

MAINTAINERS

@@ -10,10 +10,12 @@ Yi Zha <yizha1@microsoft.com> (@yizha1)
 # Repo-Level Maintainers (in alphabetical order)
 # Pattern: [First Name] [Last Name] <[Email Address]> ([GitHub Handle])
 # Note: This is for the notaryproject/tspclient-go repo
-Junjie Gao <junjiegao@microsoft.com> (@JeyJeyGao)
 Patrick Zheng <patrickzheng@microsoft.com> (@Two-Hearts)
 Shiwei Zhang <shizh@microsoft.com> (@shizhMSFT)
 
 # Emeritus Org Maintainers (in alphabetical order)
 Justin Cormack <justin.cormack@docker.com> (@justincormack)
-Steve Lasker <StevenLasker@hotmail.com> (@stevelasker)
+Steve Lasker <StevenLasker@hotmail.com> (@stevelasker)
+
+# Emeritus Repo-Level Maintainers (in alphabetical order)
+Junjie Gao <junjiegao@microsoft.com> (@JeyJeyGao)

go.mod

@@ -1,3 +1,3 @@
 module github.com/notaryproject/tspclient-go
 
-go 1.21
+go 1.23.0