Add inbox icon

CHANGELOG.md

@@ -53,6 +53,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   - `file`
   - `folder`
   - `heart`
+  - `inbox`
   - `lock`
   - `mail`
   - `minus`

icons-manifest.json

@@ -9,6 +9,7 @@
   "zoom-out",
   "filter",
   "mail",
+  "inbox",
   "scissors",
   "lock",
   "unlock",

icons/inbox.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">
+  <polyline points="22 13 16 13 14 16 10 16 8 13 2 13"/>
+  <path d="M5.47,5.19,2,13v5a2,2,0,0,0,2,2H20a2,2,0,0,0,2-2V13L18.53,5.19A2,2,0,0,0,16.7,4H7.3A2,2,0,0,0,5.47,5.19Z"/>
+</svg>
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