FDN-4581 Centralize github workflow definitions (#131)

Author: jackl

.github/workflows/pr-validator.yml

@@ -0,0 +1,8 @@
+name: "PR Title and Description Check"
+on:
+  pull_request:
+    types: [opened, edited, synchronize]
+jobs:
+  validate:
+    uses: flowcommerce/code-steward/.github/workflows/pr-validator.yml@main
+