Update pull_request_template.md (#1763)

* Update pull_request_template.md

* Update pull_request_template.md

.github/pull_request_template.md

@@ -1,3 +1,10 @@
+## Important (read before submitting)
+We are currently preparing for the upcoming 1.0 GA release. Pull requests that are not aligned with
+the current roadmap https://github.com/open-telemetry/opentelemetry-collector/blob/master/docs/roadmap.md
+and are not aimed at stabilizing and preparing the Collector for the release will not be accepted.
+
+_Delete this paragraph before submitting._
+
 **Description:** <Describe what has changed. 
 Ex. Fixing a bug - Describe the bug and how this fixes the issue.
 Ex. Adding a feature - Explain what this achieves.>
@@ -6,4 +13,6 @@ Ex. Adding a feature - Explain what this achieves.>
 
 **Testing:** < Describe what testing was performed and which tests were added.>
 
-**Documentation:** < Describe the documentation added.>
+**Documentation:** < Describe the documentation added.>
+
+_Plesae delete paragraphs that you did not use before submitting._