remove freenode (irc/chat) link on contributing guide
This resource was made by the Go community and wouldn't be possible without you! We appreciate and recognize [all contributors](https://github.com/avelino/awesome-go/graphs/contributors).
-Join us on IRC at **#awesome-go** on freenode [web access](http://webchat.freenode.net/?channels=awesome-go)
-
-
# Contribution Guidelines
> Please be aware that we want to accept your contribution, but we have **some rules to keep the minimum quality** of the packages listed here. All reviews are **not personal feedback**, even if you are a _developer reviewing your contribution_. **Sorry if we can't meet your expectations, we do our best**.
