Trait CacheableRepository - getCacheMinutes method was removed without breaking version?

[coelsman]

From version 2.7.7 to 2.7.9, method getCacheMinutes had been replaced by getCacheTime.
As I investigated, the origin PR (#762) was marked as breaking changes, the released version must be 2.8 or whatever like that.

Follow new changes, I suggest:

• Keep origin getCacheMinutes method.
• Write new method called getCacheSeconds.
• Method getCacheTime: handle difference of ttl between Laravel version and call correspond method above.

[bsormagec]

I am open to PR about this @coelsman :)