Add supported languages to README
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dialogflow/dialogflow-cordova-client,dialogflow/dialogflow-cordova-client,dialogflow/dialogflow-cordova-client,dialogflow/dialogflow-cordova-client,api-ai/api-ai-cordova,jozhao/api-ai-cordova,jozhao/api-ai-cordova,api-ai/api-ai-cordova,jozhao/api-ai-cordova,api-ai/api-ai-cordova