Migrate contracts to v0.3.5

Summary

In order to perform contract instantiations or migrations, these need to pass through governance since the Nolus network
is a semi-permissioned blockchain. This proposal aims to migrate a new version of the Leaser smart contract (v0.3.5) on the Nolus Pirin mainnet. This update seeks to simply bump the version of the Leaser contract which could not be migrated with the previous v0.3.4. The complete changelog can be seen in the Github release v0.3.5. By voting YES on this proposal, you agree to migrate this new version of the smart contracts.