docs: don't use self-closing tag for anchor element (#9456)

README.md

@@ -1,5 +1,5 @@
 <div align="center">
-  <a href="https://ollama.com" />
+  <a href="https://ollama.com">
     <img alt="ollama" height="200px" src="https://github.com/ollama/ollama/assets/3325447/0d0b44e2-8f4a-4e99-9b52-a5c1c741c8f7">
   </a>
 </div>