Changed CI config back to Xcode 10.1, updated documents

Author: sburlewapg

.travis.yml

@@ -1,11 +1,11 @@
 language: objective-c
 rvm: 2.3
 # https://docs.travis-ci.com/user/reference/osx
-osx_image: xcode10.2
+osx_image: xcode10.1
 env:
   global:
     - IOS_SIMULATOR="iPhone 6s"
-    - IOS_VERSION="12.2"
+    - IOS_VERSION="12.1"
 matrix:
   include:
     - env: BUILD_SCHEME="SQLite iOS"

Documentation/Index.md

@@ -68,7 +68,7 @@
 ## Installation
 
 > _Note:_ SQLite.swift requires Swift 4.2 (and
-> [Xcode 9.3](https://developer.apple.com/xcode/downloads/)) or greater.
+> [Xcode 10](https://developer.apple.com/xcode/downloads/)) or greater.
 
 
 ### Carthage

README.md

@@ -112,7 +112,7 @@ and the [companion repository][SQLiteDataAccessLayer2].
 
 ## Installation
 
-> _Note:_ SQLite.swift requires Swift 4.2 (and [Xcode][] 9.3).
+> _Note:_ SQLite.swift requires Swift 4.2 (and [Xcode][] 10).
 
 ### Carthage