chore: Skip all branch builds.

Dependabot is putting a lot of load on travis because it creates
branches in the upstream repo.

Author: iphydf

.github/settings.yml

@@ -5,7 +5,6 @@ repository:
   name: js-toxcore-c
   description: Node bindings for toxcore
   topics: toxcore, javascript
-  has_issues: true
 
 branches:
   - name: "master"

.travis.yml

@@ -42,3 +42,7 @@ script:
   - npm run test
   - npm run report-coverage
   - if [ "$CHECK_FORMAT" = true ]; then npm run format && git diff --exit-code; fi
+
+# Only build pull requests and releases, don't build master on pushes,
+# except through api or cron.
+if: type IN (pull_request, api, cron) OR tag IS present