Upgrade BurntSushi/toml to avoid decoding bug

[lackstein]

There's a bug (see BurntSushi/toml#339) in BurnSushi/toml v0.4.1 that was causing empty arrays to be decoded into a nil interface.

If you print out the interface it looks correct:

map[args:[[]] custom:map[expires_in:5m] queue:default retry:0 type:analysisWatchdog]

But when you marshal it into JSON:

{"args":[null],"custom":{"expires_in":"5m"},"jobtype":"analysisWatchdog","queue":"default","retry":0,"type":"analysisWatchdog"}

Looking at the interface with spew it's clear that the inner array in args is nil:

(map[string]interface {}) (len=5) {
 (string) (len=4) "type": (string) (len=16) "analysisWatchdog",
 (string) (len=5) "queue": (string) (len=7) "default",
 (string) (len=5) "retry": (int64) 0,
 (string) (len=4) "args": ([]interface {}) (len=1 cap=1) {
  ([]interface {}) <nil>
 },
 (string) (len=6) "custom": (map[string]interface {}) (len=1) {
  (string) (len=10) "expires_in": (string) (len=2) "5m"
 }
}

[elldritch]

Good call on the linting fixes too.

FYI, the maximally reliable way to determine the real shape of data is fmt.Printf using the %#v verb.