Update distros

packagecore.yaml

@@ -16,7 +16,7 @@ packages:
       - ncurses
       - readline
     container: "archlinux/base"
-  centos7.2:
+  centos7.4:
     builddeps:
       - make
       - gcc
@@ -29,7 +29,7 @@ packages:
     commands:
       pre:
         - yum install epel-release
-  centos7.3:
+  centos7.5:
     builddeps:
       - make
       - gcc
@@ -42,7 +42,7 @@ packages:
     commands:
       pre:
         - yum install epel-release
-  centos7.4:
+  centos7.6:
     builddeps:
       - make
       - gcc