Update carthage; use correct git sha to test

Author: jberkel

.travis.yml

@@ -18,5 +18,7 @@ matrix:
 before_install:
   - gem update bundler
   - gem install xcpretty --no-document
+  - brew update
+  - brew outdated carthage || brew upgrade carthage
 script:
   - ./run-tests.sh

Tests/Carthage/Cartfile

@@ -5,6 +5,11 @@ CARTHAGE_DIR := Carthage
 CARTHAGE_ARGS := --no-use-binaries
 CARTHAGE_TOOLCHAIN := com.apple.dt.toolchain.Swift_3_0
 CARTHAGE_CMDLINE := --configuration $(CARTHAGE_CONFIGURATION) --platform $(CARTHAGE_PLATFORM) --toolchain $(CARTHAGE_TOOLCHAIN) $(CARTHAGE_ARGS)
+TRAVIS_COMMIT ?= master
+TRAVIS_REPO_SLUG ?= stephencelis/SQLite.swift
 
 test: $(CARTHAGE) Cartfile
 	$< bootstrap $(CARTHAGE_CMDLINE)
+
+Cartfile:
+	echo 'github "$(TRAVIS_REPO_SLUG)" "$(TRAVIS_COMMIT)"' > $@