Support new `--sourcemap=[auto|file|inline|none]` as well as old `--sourcemap` option

sass.js.patch

diff --git tasks/sass.js tasks/sass.js
index 96ac499..85db65c 100644
--- tasks/sass.js
+++ tasks/sass.js
@@ -29,6 +29,7 @@ module.exports = function (grunt) {
     var passedArgs;
     var bundleExec;
     var banner;
+    var sourcemap;
 
     try {
       which.sync('sass');
@@ -45,7 +46,19 @@ module.exports = function (grunt) {
       delete options.banner;
     }
 
+    // Support new `--sourcemap=[auto|file|inline|none]` as well as old `--sourcemap` option
+    if (options.sourcemap) {
+      if (typeof options.sourcemap === 'boolean') {
+        sourcemap = '--sourcemap';
+      } else {
+        sourcemap = '--sourcemap=' + options.sourcemap;
+      }
+
+      delete options.sourcemap;
+    }
+
     passedArgs = dargs(options, ['bundleExec']);
+    passedArgs.push(sourcemap);
     bundleExec = options.bundleExec;
 
     async.eachLimit(this.files, numCPUs, function (file, next) {