Update and rename campaignmonitor.yaml to campaignmonitor-takeover.yaml

1. Following filename formatting & id template = filename 
2. Added link to github issue

takeovers/campaignmonitor-takeover.yaml

@@ -5,7 +5,7 @@ info:
   author: pdteam
   severity: high
   reference:
-    - https://github.com/EdOverflow/can-i-take-over-xyz
+    - https://github.com/EdOverflow/can-i-take-over-xyz/issues/275
   tags: takeover
 
 requests:
@@ -23,4 +23,4 @@ requests:
         words:
           - '<strong>Trying to access your account?</strong>'
           - 'or <a href="mailto:help@createsend.com'
-        condition: and
+        condition: and