Add pull_request_template.md (#308)

* Add `pull_request_template.md`

* Change template

.github/pull_request_template.md

@@ -0,0 +1,7 @@
+<!-- If you added changes to files in the `node` directory or any other changes that would require a re-deployment of the collator nodes, please add the following line to the PR description:
+@pendulum-chain/product: This PR adds changes to the node client code that require a **redeployment of the collator nodes** to take effect. 
+Please ensure that the collator nodes are redeployed after this PR is merged.  
+-->
+
+<!-- Replace xx with the issue number that is fixed by this pull request. -->
+Closes #xx.