Fix icon button centering

RELEASE-NOTES.md

@@ -8,6 +8,7 @@
 - **Dropdown** - Added new setting `filterAPIResults` which when enabled will filter results locally by query after API returns, allowing your API call to return the full dropdown dataset. **Thanks @enix223** #4815
 
 **Bugs**
+- **Button** - Fixed issue where css specificity caused `icon buttons` to not center correctly #4487
 - **Dropdown** - Fix bug where `scrolling menu` or `scrolling dropdown` would have excessive right padding by removing scrollbar width from calculation (no longer necessary in modern browsers)
 - **Comments** - `small`, `large` and other comment sizes now default to global size variables.
 

src/definitions/elements/button.less

@@ -693,7 +693,7 @@
 .ui.icon.buttons .button > .icon,
 .ui.icon.button > .icon {
   opacity: @iconButtonOpacity;
-  margin: 0em;
+  margin: 0em !important;
   vertical-align: top;
 }