chore: update README.md to include client provider import (#668)

Signed-off-by: Juan Bernal <[email protected]>

Author: juanparadox

libs/providers/launchdarkly-client/README.md

@@ -13,6 +13,8 @@ $ npm install @openfeature/launchdarkly-client-provider
 ## Sample initialization
 
 ```ts
+import { LaunchDarklyClientProvider } from '@openfeature/launchdarkly-client-provider';
+
 // initialize provider
 const clientEnvKey = 'LDEnvironmentID';