PRs: use icons in descriptions (#517)

Update PR template to provide guidance on title icons.

Add job to verify icon in PR title.

Make sure dependabot PRs titles are prefixed with 🌱.

Signed-off-by: Andy Goldstein <[email protected]>

Author: ncdc

.github/dependabot.yml

@@ -8,3 +8,5 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+    commit-message:
+      prefix: ":seedling:"

.github/pull_request_template.md

@@ -1,3 +1,14 @@
+<!--
+Please prefix the title of this PR with one of the following icons:
+
+    * ⚠ (:warning:, major/breaking change)
+    * ✨ (:sparkles:, minor/compatible change)
+    * 🐛 (:bug:, patch/bug fix)
+    * 📖 (:book:, docs)
+    * 🌱 (:seedling:, other)
+
+-->
+
 # Description
 
 <!--

.github/workflows/pr-title.yaml

@@ -0,0 +1,13 @@
+on:
+  pull_request_target:
+    types: [opened, edited, reopened, synchronize]
+
+jobs:
+  pr-title:
+    runs-on: ubuntu-latest
+    name: Verify PR title
+    steps:
+    - name: Verify PR title
+      uses: kubernetes-sigs/[email protected]
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}