Add triangle icon

CHANGELOG.md

@@ -46,6 +46,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   - `sunset`
   - `thumbs-down`
   - `thumbs-up`
+  - `triangle`
   - `user-minus`
   - `user-plus`
   - `video-off`

icons-manifest.json

@@ -68,6 +68,7 @@
   "printer",
   "edit",
   "octagon",
+  "triangle",
   "square",
   "plus-square",
   "minus-square",

icons/triangle.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="#000" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+  <path d="M10.29,3.86,1.82,18a2,2,0,0,0,1.71,3H20.47a2,2,0,0,0,1.71-3L13.71,3.86A2,2,0,0,0,10.29,3.86Z"/>
+</svg>
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