Add octagon icon

CHANGELOG.md

@@ -32,6 +32,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   - `map-pin`
   - `mic-off`
   - `music`
+  - `octagon`
   - `phone`
   - `phone-call`
   - `phone-forwarded`

icons-manifest.json

@@ -67,6 +67,7 @@
   "clock",
   "printer",
   "edit",
+  "octagon",
   "square",
   "plus-square",
   "minus-square",

icons/octagon.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">
+  <polygon points="7.86 2 16.14 2 22 7.86 22 16.14 16.14 22 7.86 22 2 16.14 2 7.86 7.86 2"/>
+</svg>
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