Upgrade Go version to 1.15

rs · rs · commit 76d0021d214f · 2020-09-21T19:22:34.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,6 @@
 sudo: required
 language: go
-go: '1.10'
+go: '1.15'
 matrix:
   allow_failures:
   - go: master
