remove travis from required checks for merging PRs (#136)

.asf.yaml

diff --git a/.asf.yaml b/.asf.yaml
index acdd626..03ed41a 100644
--- a/.asf.yaml
+++ b/.asf.yaml
@@ -35,8 +35,6 @@
     master:
       required_status_checks:
         strict: false
-        contexts:
-          - "Travis CI - Pull Request"
       required_pull_request_reviews:
         required_appoving_review_count: 1
       required_signatures: false