replace .title with .header

Author: Dhruvi16

webpack/sass/main.scss

@@ -218,7 +218,7 @@ code {
 }
 
 // Common Title section
-.title {
+.header {
   background-color: $color-lighter-gray;
 
   .container {
@@ -368,7 +368,7 @@ code {
 
 // Author Post page
 .author-posts {
-  .title {
+  .header {
     .container {
       .image {
         width: 9.5rem;