added auto yes for oracle license agreement

Author: holgerbrandl

.travis.yml

@@ -31,7 +31,7 @@ install:
   - source "/home/travis/.sdkman/bin/sdkman-init.sh"
 
   ## install kotlin and maven
-  - sdk install java 8u144-oracle
+  - bash -c 'yes | sdk install java 8u144-oracle'
   - sdk install maven
   - sdk install kotlin
   - sdk install gradle