Update .travis.yml

.travis.yml

@@ -6,7 +6,7 @@ before_install:
   - export LANG=en_US.UTF-8
 
 script:
-  - xctool -workspace 'Masonry.xcworkspace' -scheme 'Masonry iOS Tests' -configuration Debug -sdk iphonesimulator7.0 clean build test ARCHS=i386 VALID_ARCHS=i386 ONLY_ACTIVE_ARCH=NO GCC_INSTRUMENT_PROGRAM_FLOW_ARCS=YES GCC_GENERATE_TEST_COVERAGE_FILES=YES
+  - xctool -workspace 'Masonry.xcworkspace' -scheme 'Masonry iOS Tests' -configuration Debug -sdk iphonesimulator8.1 clean build test ARCHS=i386 VALID_ARCHS=i386 ONLY_ACTIVE_ARCH=NO GCC_INSTRUMENT_PROGRAM_FLOW_ARCS=YES GCC_GENERATE_TEST_COVERAGE_FILES=YES
 
 after_success:
   - ./script/coveralls.sh