Fix cabal file

maksbotan · maksbotan · commit 20d5b85f4d3a · 2021-06-04T00:54:24.000+03:00
diff --git a/servant-multipart-client/servant-multipart-client.cabal b/servant-multipart-client/servant-multipart-client.cabal
@@ -63,4 +63,4 @@ executable server
     , warp
 
   if impl(ghcjs)
-    buildable: false
+    buildable: False
