replacing the placeholder with the path to Unique image for the Git branch and alt message

Author: Tobias-Amaechina

Wireframe/index.html

@@ -34,7 +34,7 @@ <h2>What is the Purpose of a Wireframe?</h2>
         <a href="https://www.productplan.com/glossary/wireframe">Read more</a>
       </article>
       <article>
-        <img src="placeholder.svg" alt="" />
+        <img src="git_branch.png" alt="A Git branch diagram"/>
         <h2>What Is a Git Branch?</h2>
         <p>
             In Git, a <em>branch</em> is like a separate workspace