"1.10" is put into quotes because otherwise Travis parses that as 1.1 -

Alkorin · Alkorin · commit aa2008a6c465 · 2018-07-17T23:19:51.000+02:00
see travis-ci/travis-ci#9247
diff --git a/.travis.yml b/.travis.yml
@@ -1,7 +1,7 @@
 language: go
 
 go:
-- 1.10
+- "1.10"
 
 after_success:
   - test -n "$TRAVIS_TAG" && curl -sL https://git.io/goreleaser | bash
