I have to develop the same app for Google Smart Home and Alexa Smart Home, is there something like https://www.jovo.tech/ for skills and actions to build the same app for both platform?
No, at this moment there is not a tool that allows you to build one piece of software across both platforms. While there are services like Dialogflow which can work with Assistant and Alexa, it is designed for conversational projects, it doesn't create projects built on top of Google Assistant's smart home platform.
Smart home on Google Assistant is non-conversational. You don't say "Hey Google, talk to Roomba" to start controlling your vacuum. Instead, you say "Hey Google, start my Roomba" to directly get it started. This is done through more structured grammars that come out of the box instead of having to be created through Dialogflow.
I am less familiar with developing smart home skills, so I don't know how they differ from standard conversational skills. Ultimately though, the deep integration of smart home in Assistant has created a new unique set of requirements that no intermediary service has implemented.