Update logo for dark mode (#67)

Author: ameen4455

README.md

@@ -1,5 +1,8 @@
 <p align="center">
-  <a href="https://www.parseable.io" target="_blank"><img src="https://raw.githubusercontent.com/parseablehq/.github/main/images/logo.svg" alt="Parseable" width="600" height="150" /></a>
+  <span">
+    <img src="https://raw.githubusercontent.com/parseablehq/.github/main/images/logo.svg#gh-light-mode-only" alt="Parseable" width="600" height="150" />
+    <img src="https://raw.githubusercontent.com/parseablehq/.github/main/images/logo-dark.png#gh-dark-mode-only" alt="Parseable" width="650"/>
+  </a> 
 </p>
 
 <p align="center">