Merge pull request #1371 from NivekT/versions_main

Change versions.html to point at `main` instead of `master`

Author: svekars

docs/versions.html

@@ -18,7 +18,7 @@ <h1> PyTorch Documentation </h1>
       <p class="caption"><span class="caption-text">Pick a version</span></p>
       <ul>
         <li class="toctree-l1">
-          <a class="reference internal" href="master/">master (unstable)</a>
+          <a class="reference internal" href="main/">main (unstable)</a>
         </li>
          <li class="toctree-l1">
           <a class="reference internal" href="2.0/">v2.0.0 (stable release)</a>