chore(ci): run e2e tests only for users which are contributors

This is because we don't want ot publicly share InfluxDB Enterprise license key.

Author: bednar

.github/workflows/chronograf-cypress-tests.yaml

@@ -8,6 +8,13 @@ on:
 
 jobs:
   e2e:
+    if: |
+      github.event_name == 'push' ||
+      (github.event_name == 'pull_request' && (
+        github.event.pull_request.author_association == 'OWNER' ||
+        github.event.pull_request.author_association == 'MEMBER' ||
+        github.event.pull_request.author_association == 'COLLABORATOR'
+      ))
     runs-on: ubuntu-latest
     timeout-minutes: 30
     env: