Fix links on GitHub issue templates (#150)

Signed-off-by: Juan Luis Cano Rodríguez <juan_luis_cano@mckinsey.com>

.github/ISSUE_TEMPLATE/config.yml

@@ -1,10 +1,10 @@
 blank_issues_enabled: false
 contact_links:
-  - name: Discord server
+  - name: Slack workspace
     about: Come chat with the community!
-    url: https://discord.gg/akJDeVaxnB
+    url: https://slack.kedro.org
   - name: Documentation
-    url: https://kedro.readthedocs.io/en/stable/
+    url: https://docs.kedro.org
     about: To learn more about how Kedro works
   - name: Case studies, articles and video tutorials
     url: https://github.com/kedro-org/kedro-community