Consider using GitHub releases so that pinning versions is easier

[JohnRoesler]

Right now, in order to pin to a specific version of gocron - I have to know the commit and commit date/time I want to point on master.

If we use github releases - then pulling with go mod allows to set the version pin. For example:

- 	github.com/jasonlvhit/gocron v0.0.0-20191103124442-96e810119cd2
+ 	github.com/jasonlvhit/gocron v1.0.1

[JohnRoesler]

@preslavrachev @Streppel

[Streppel]

Completely agree. I'll be creating a version 0.5 as a pre-release as we still need to merge a really important PR that adds production safety (but currently has some code conflicts) and work on some code and tests to fix problems like #19 and #50 in order to consider this package to be production ready. What do you think?

[JohnRoesler]

Yes i think that makes sense. A big thing I'd like to see is a way to have errors passed back out (channel maybe) so that I could decide how to handle different errors that may occur during my cron's run.

[Streppel]

And from now on we have our pre-release version 0.1!

https://github.com/jasonlvhit/gocron/releases/tag/0.1