Remove support for Puppet 5 and Ubuntu 18.04

We removed support for these during wallaby cycle. Because we are now
transitioning victoria and older branches to EOL, we no longer have to
support these old versions now.

Change-Id: I7574de03ada51b375195f025c7fee6c73e163655

metadata.json

@@ -10,7 +10,7 @@
     "requirements": [
         {
             "name": "puppet",
-            "version_requirement": ">= 5.0.0 < 8.0.0"
+            "version_requirement": ">= 6.0.0 < 8.0.0"
         }
     ],
     "operatingsystem_support": [
@@ -38,7 +38,6 @@
         {
             "operatingsystem": "Ubuntu",
             "operatingsystemrelease": [
-                "18.04",
                 "20.04",
                 "22.04"
             ]

releasenotes/notes/remove-puppet-5-and-ubuntu-18.04-99332d5c63fa98f7.yaml

@@ -0,0 +1,8 @@
+---
+upgrade:
+  - |
+    Ubuntu 18.04 is no longer supported.
+
+  - |
+    Puppet 5 support has been removed. Now this module supports only Puppet 6
+    or later.