fix(Textarea): correct font sizes for size variants

- size=sm uses 14px (text-base)
- size=md uses 16px (text-lg)
- size=lg uses 18px (text-2xl)
- size=xl uses 20px (text-3xl) to preserve size progression
Closes #738

Author: Pranit-DC

src/components/Textarea/Textarea.vue

@@ -118,9 +118,9 @@ const attrsWithoutClassStyle = computed(() => {
 const inputClasses = computed(() => {
   let sizeClasses = {
     sm: 'text-base rounded',
-    md: 'text-base rounded',
-    lg: 'text-lg rounded-md',
-    xl: 'text-2xl rounded-md',
+    md: 'text-lg rounded',
+    lg: 'text-2xl rounded-md',
+    xl: 'text-3xl rounded-md',
   }[props.size]
 
   let paddingClasses = {