update watch os in travis script

Author: tristanhimmelman

.travis.yml

@@ -17,7 +17,7 @@ env:
     #macOS
     - DESTINATION="arch=x86_64"                      SCHEME="$OSX_FRAMEWORK_SCHEME"      RUN_TESTS="YES"
     #watchOS
-    - DESTINATION="OS=4.3,name=Apple Watch - 42mm"   SCHEME="$WATCHOS_FRAMEWORK_SCHEME"  RUN_TESTS="NO"
+    - DESTINATION="OS=6.1,name=Apple Watch - 42mm"   SCHEME="$WATCHOS_FRAMEWORK_SCHEME"  RUN_TESTS="NO"
     #tvOS
     - DESTINATION="OS=11.4,name=Apple TV 4K"         SCHEME="$TVOS_FRAMEWORK_SCHEME"     RUN_TESTS="YES"