README: Update number of supported languages

Seems the README was never updated to account for WebAssembly...

Reported-by: Palmese Davide Mattia <https://github.com/PalmeseMattia>
Closes: #1376
Signed-off-by: Andrew Clayton <[email protected]>

Author: ac000

README.md

@@ -12,7 +12,7 @@ NGINX Unit is a lightweight and versatile open-source server that has
 two primary capabilities:
 
 - serves static media assets,
-- runs application code in seven languages.
+- runs application code in eight languages.
 
 Unit compresses several layers of the modern application stack into a potent,
 coherent solution with a focus on performance, low latency, and scalability. It