Add Go 1.15 to supported versions

fffinkel · fffinkel · commit 64663d1d479c · 2020-11-30T00:14:29.000Z
diff --git a/.travis.yml b/.travis.yml
@@ -6,6 +6,7 @@ go:
   - "1.12.x"
   - "1.13.x"
   - "1.14.x"
+  - "1.15.x"
 
 before_install:
   - go get -t ./...
