chore: expand account names in CODEOWNERS (#121)

Closes #120

Signed-off-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>

Author: gbartolini

CODEOWNERS

@@ -2,4 +2,4 @@
 # responsible for code in a repository. For details, please refer to
 # https://docs.github.com/en/free-pro-team@latest/github/creating-cloning-and-archiving-repositories/about-code-owners
 
-* @cloudnative-pg/maintainers @SaxenaAnushka102
+* @leonardoce @mnencia @gbartolini @fcanovai @SaxenaAnushka102