Add CODEOWNERS to the repmgr repo

Signed-off-by: Martín Marqués <martin.marques@enterprisedb.com>

.github/CODEOWNERS

@@ -0,0 +1,7 @@
+# Each line is a file pattern followed by one or more owners.
+
+# These owners will be the default owners for everything in
+# the repo. Unless a later match takes precedence,
+# @global-owner1 and @global-owner2 will be requested for
+# review when someone opens a pull request.
+*       @EnterpriseDB/repmgr-dev

README.md

@@ -7,8 +7,8 @@ replication capabilities with utilities to set up standby servers, monitor
 replication, and perform administrative tasks such as failover or switchover
 operations.
 
-The most recent `repmgr` version (5.4.1) supports all PostgreSQL versions from
-10 to 16.
+The most recent `repmgr` version (5.3.2) supports all PostgreSQL versions from
+9.5 to 15. PostgreSQL 9.4 is also supported, with some restrictions.
 
 `repmgr` is distributed under the GNU GPL 3 and maintained by EnterpriseDB.
 
@@ -56,6 +56,8 @@ There is a mailing list/forum to discuss contributions or issues:
 
 * https://groups.google.com/group/repmgr
 
+The IRC channel #repmgr is registered with freenode.
+
 Please report bugs and other issues to:
 
 * https://github.com/EnterpriseDB/repmgr
@@ -67,14 +69,6 @@ news are always welcome.
 
 Thanks from the repmgr core team.
 
-* Ian Barwick
-* Israel Barth
-* Mario González
-* Martín Marqués
-* Gianni Ciolli
-
-Past contributors:
-
 * Jaime Casanova
 * Abhijit Menon-Sen
 * Simon Riggs