Updated themes (#1145)

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Author: github-actions[bot]

arduino-ide-extension/src/browser/data/default.color-theme.json

@@ -22,7 +22,7 @@
     "menu.selectionBackground": "#dae3e3",
     "menu.selectionForeground": "#212121",
     "editorGroupHeader.tabsBackground": "#ecf1f1",
-    "button.background": "#008184",
+    "button.background": "#7fcbcd",
     "button.foreground": "#f7f9f9",
     "button.hoverBackground": "#005C5F",
     "titleBar.activeBackground": "#006d70",