correct the proxy_name format

Author: Vlasis-Perdikidis

.env.template

@@ -2,7 +2,7 @@
 GITHUB_TOKEN=
 
 # Apigee proxy name to be used for test execution
-# nhs-notify-supplier--internal-dev--nhs-notify-supplier-prxxx
+# nhs-notify-supplier--internal-dev--nhs-notify-supplier-PR-xxx
 PROXY_NAME=
 
 # APIM env to run e2e tests against, other options are: ref, int, prod