Update Surge to Swift 4

[shahmishal]

No description provided.

[shahmishal]

@swift-ci test

[shahmishal]

We need to update scheme of the project to be

Schemes:
        Surge-iOS
        Surge-macOS
        Surge-tvOS
        Surge-watchOS

[clackary]

Yep, running a test locally to verify schemes are correct.

[shahmishal]

@swift-ci test

[clackary]

Yeah, looks like project_precommit_check passes with these changes. Thanks!

./project_precommit_check Surge --earliest-compatible-swift-version 4.2
** CHECK **
--- Validating Surge Swift version 4.2 compatibility ---
--- Project configured to be compatible with Swift 4.2 ---
--- Checking Surge platform compatibility with Darwin ---
--- Platform compatibility check succeeded ---
--- Locating swiftc executable ---
$ xcrun -f swiftc
--- Checking installed Swift version ---
$ /Applications/Xcodes/PublicGMs/Xcode-10-GM.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc --version
--- Version check succeeded ---
--- Executing build actions ---
$ ./runner.py --swift-branch swift-4.2-branch --swiftc /Applications/Xcodes/PublicGMs/Xcode-10-GM.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc --projects projects.json --include-repos 'path == "Surge"' --include-versions 'version == "4.2"' --include-actions 'action.startswith("Build")'
PASS: Surge, 4.2, 38a328, Surge-iOS, generic/platform=iOS
PASS: Surge, 4.2, 38a328, Surge-tvOS, generic/platform=tvOS
PASS: Surge, 4.2, 38a328, Surge-watchOS, generic/platform=watchOS
PASS: Surge, 4.2, 38a328, Surge-macOS, generic/platform=macOS
========================================
Action Summary:
     Passed: 4
     Failed: 0
    XFailed: 0
    UPassed: 0
      Total: 4
========================================
Repository Summary:
      Total: 1
========================================
Result: PASS
========================================
--- Surge checked successfully against Swift 4.2 ---