Update README.md

Author: norio-nomura

README.md

@@ -8,11 +8,11 @@ LinuxSupport for Xcode is an Xcode Extension.
 - Generate allTests for subclasses of `XCTestCase`
 
 ## Requirements
-- Xcode 8.0
+- Xcode 9.0
 
 ## Install
 
-1. Install Xcode 8
+1. Install Xcode 9
 2. If you are using OS X 10.11, running `sudo /usr/libexec/xpccachectl` and rebooting are required for using Xcode Extension.
 3. Clone this repository. _(Using submodules!)_
 4. Run `xcodebuild -workspace LinuxSupportForXcode.xcworkspace -scheme LinuxSupportForXcode install DSTROOT=~` and install `~/Applications/LinuxSupportForXcode.app`