fix: typo in the meta theme color tag

Author: CodeMyst

client/src/app.html

@@ -18,7 +18,7 @@
             content="a powerful website for storing and sharing text and code snippets. completely free and open source."
         />
 
-        <meta name="themecolor" content="#ee720d" />
+        <meta name="theme-color" content="#ee720d" />
 
         <meta property="og:type" content="website" />
         <meta property="og:url" content="https://paste.myst.rs/" />