Empty template name should fail the action for issuescreate

[sfc-gh-eraigosa]

We found a small bug when running /issuescreate. If we don't specify a message or template name, we still pass the action but it throws an error which doesn't result in the action failing. Really we should check if a message or template name is actually passed and otherwise throw an error and fail the action.

The error looks like:

(node:2424) UnhandledPromiseRejectionWarning: Error: EISDIR: illegal operation on a directory, read
    at Object.readSync (fs.js:506:3)
    at tryReadSync (fs.js:331:20)
    at Object.readFileSync (fs.js:368:19)
    at Object.<anonymous> (/home/runner/work/_actions/wenlock/behest/wenlock-add-commands/dist/index.js:6357:23)
    at Generator.next (<anonymous>)
    at fulfilled (/home/runner/work/_actions/wenlock/behest/wenlock-add-commands/dist/index.js:6265:58)

I'm hoping to have a little time this week to fix that.