Fixed invalid reference to 'head' on non-windows systems.

Author: RandomEngy

package.json

@@ -2,7 +2,7 @@
 	"name": "git-diff-and-merge-tool",
 	"displayName": "Git Diff and Merge Tool",
 	"description": "Launch git difftool and mergetool from VSCode.",
-	"version": "1.0.3",
+	"version": "1.0.4",
 	"author": {
 		"name": "David Rickard",
 		"email": "david.rickard@gmail.com"

src/extension.ts

@@ -54,7 +54,7 @@ export function activate(context: vscode.ExtensionContext) {
 	let diffCommand = vscode.commands.registerCommand('gitdiffandmergetool.diff', (param: any) => {
 		executeOperation(
 			param,
-			(targetFile: string) => { return ['difftool', '-y', 'head', targetFile]; },
+			(targetFile: string) => { return ['difftool', '-y', 'HEAD', targetFile]; },
 			(targetFile: string) => { return 'Launching diff tool for ' + targetFile; });
 	});