fix: add missing 'posting_json_metadata' field in Account interface

Did you test the library after adding it?

I've not been able to successfully run the unit tests. Plenty of errors even before my change. But I cloned the repository, built locally and imported into another project with this:

package.json:

...
"@hiveio/dhive": "file:../dhive",
...

And it worked. Actually it worked even before my change, but now I don't have a warning about the missing property.

Let me know if I have to do something different as this is the first time I push code to dhive :)

It's fine as long as it works. Sometimes things break even with simple changes. Tests need a testnet node and that's why we can't keep them working forever. We just fixed them last hardfork.

merged

mentioned in commit 0ac8de20