fix pr heading

Signed-off-by: Max Cao <macao@redhat.com>

.github/pull_request_template.md

@@ -1,11 +1,12 @@
-# Welcome to Cryostat! Before contributing, make sure you have:
+# Welcome to Cryostat! 👋
+## Before contributing, make sure you have:
 * [ ] Read the [contributing guidelines](https://github.com/cryostatio/cryostat/blob/main/CONTRIBUTING.md)
 * [ ] Rebased your branch on top the latest upstream `main` branch
 * [ ] Linked a relevant issue which this PR resolves
 * [ ] Linked any other relevant issues, PR's, or documentation (if applicable)
 * [ ] Attached at least one of the following labels is attached to the PR: [chore,ci,docs,feat,fix,test]
 * [ ] Request review from at least one of the following [reviewers](https://github.com/orgs/cryostatio/teams/reviewers)
-* [ ] Signed the last commit 
+* [ ] Signed the last commit (`git commit --amend --signoff`)
 _______________________________________________
 
 Fixes: #<issue number>