chore: update Aragon Chat links (aragon#1093)

CONTRIBUTING.md

@@ -42,7 +42,7 @@ If the answer to either of those two questions are "yes", then you're probably d
 ## Fixing issues
 
 1. [Find an issue](https://github.com/aragon/aragon-apps/issues) that you are interested in.
-    - You may want to ask on the issue or on Aragon Chat's [#dev channel](https://aragon.chat/channel/dev) if anyone has already started working on the issue.
+    - You may want to ask on the issue or in our Spectrum [App development channel](https://spectrum.chat/aragon/app-development) if anyone has already started working on the issue.
 1. Fork and clone a local copy of the repository.
 1. Make the appropriate changes for the issue you are trying to address or the feature that you want to add.
 1. Push the changes to the remote repository.
@@ -93,4 +93,4 @@ As `next` becomes ready, merge `next` onto `master` with a rebase.
 
 ## Community
 
-If you need help, please reach out to Aragon core contributors and community members in the Aragon Chat [#dev](https://aragon.chat/channel/dev) and [#dev-help](https://aragon.chat/channel/dev-help) channels. We'd love to hear from you and know what you're working on!
+If you need help, please reach out to Aragon core contributors and community members in our Spectrum [App development channel](https://spectrum.chat/aragon/app-development).  We'd love to hear from you and know what you're working on!

README.md

@@ -57,3 +57,7 @@ If you come across an issue with Aragon, do a search in the [Issues](https://git
 - If the issue you found has been reported and is still open, and the details match your issue, give a "thumbs up" to the relevant posts in the issue thread to signal that you have the same issue. No further action is required on your part.
 - If the issue you found has been reported and is still open, but the issue is missing some details, you can add a comment to the issue thread describing the additional details.
 - If the issue you found has been reported but has been closed, you can comment on the closed issue thread and ask to have the issue reopened because you are still experiencing the issue. Alternatively, you can open a new issue, reference the closed issue by number or link, and state that you are still experiencing the issue. Provide any additional details in your post so we can better understand the issue and how to fix it.
+
+## Help
+
+For help and support, feel free to contact us at any time on our Spectrum [App development channel](https://spectrum.chat/aragon/app-development).