fix(ui5-popover): bottom border radius (#34)

Fixes #30

Author: ilhan007

packages/main/src/themes/base/Popup.less

@@ -62,6 +62,12 @@
 	background-color: @sapUiGroupContentBackground;
 }
 
+.sapMPopup .sapMPopupContent,
+.sapMPopup .sapMPopupFooter {
+	border-bottom-left-radius: .25rem;
+	border-bottom-right-radius: .25rem;
+}
+
 .sapMPopup .sapMPopupScroll {
 	vertical-align: middle;
 	box-sizing: border-box;