fix: resolve #360 make style consistent across outlines

This changes make the style consistent across the first three
 headline line levels

 1. The first level add CSS prop initial
 2. The second level change prop from capital to inital
 3. No change

src/editors/data/constants/tinyMCEStyles.js

@@ -120,6 +120,7 @@ const getStyles = () => (
       font-size: 2em;
       line-height: 1.4em;
       margin: 0 0 1.41575em 0;
+      text-transform: initial;
   }
   .mce-content-body h2,
   .mce-content-body .hd-2 {
@@ -129,7 +130,7 @@ const getStyles = () => (
       font-weight: 300;
       font-size: 1.2em;
       line-height: 1.2em;
-      text-transform: uppercase;
+      text-transform: initial;
   }
   .mce-content-body h3,
   .mce-content-body .hd-3 {