Update drizzle-store types to solidity 0.7

[youngkidwarrior]

The abi specification for soliditiy 0.7 has been updated since 0.5.3

name: the name of the function;
inputs: an array of objects, each of which contains:
   name: the name of the parameter.
   type: the canonical type of the parameter (more below).
   components: used for tuple types (more below).
outputs: an array of objects similar to inputs.
stateMutability: a string with one of the following values: pure (specified to not read blockchain state), view (specified to not modify the blockchain state), nonpayable (function does not accept Ether - the default) and payable (function accepts Ether). 

It looks like 0.7 has some cool new features, I could do some work to update drizzle to support 0.7