Add Emacs 26.1 to the Travis CI build

Author: bbatsov

.travis.yml

@@ -9,7 +9,9 @@ env:
   - EMACS_BINARY=emacs-25.1-travis MAKE_TEST=test-bytecomp
   - EMACS_BINARY=emacs-25.2-travis MAKE_TEST=test
   - EMACS_BINARY=emacs-25.2-travis MAKE_TEST=test-bytecomp
-  - EMACS_BINARY=emacs-25.2-travis MAKE_TEST=test-checks
+  - EMACS_BINARY=emacs-26.1-travis MAKE_TEST=test
+  - EMACS_BINARY=emacs-26.1-travis MAKE_TEST=test-bytecomp
+  - EMACS_BINARY=emacs-26.1-travis MAKE_TEST=test-checks
   - EMACS_BINARY=emacs-git-snapshot-travis
 matrix:
   allow_failures: