docs: fix some typos

Author: ghiscoding

README.md

@@ -101,13 +101,13 @@ This modernization provides a huge decrease in the final build size, with only 1
 
 ## Major Changes
 
-### version 3.0
+#### version 3.0
 - initial release (forked from original `excel-builder` library)
 
-### version 4.0
+#### version 4.0
 - build as ESM-Only and drop CJS (CommonJS) build (aka `require()`)
 
-### version 5.0
+#### version 5.0
 - drop the legacy IIFE build and the use of `window` object (typically used when loading as the legacy `<script>`).
 
 ### Used by

packages/excel-builder-vanilla/README.md

@@ -48,11 +48,11 @@ downloadExcelFile(artistWorkbook, 'Artist WB.xlsx');
 
 ## Major Changes
 
-### version 3.0
+#### version 3.0
 - initial release (forked from original `excel-builder` library)
 
-### version 4.0
+#### version 4.0
 - build as ESM-Only and drop CJS (CommonJS) build (aka `require()`)
 
-### version 5.0
+#### version 5.0
 - drop the legacy IIFE build and the use of `window` object (typically used when loading as the legacy `<script>`).