Upgrade to latest nodemon to fix restart

The grunt-nodemon module we were using is no longer
maintained and is stuck on a 1.x version of nodemon.

At that version, node-red doesn't restart properly
due to our increased signal handling in the core.

This change removes grunt-nodemon and replaces it
with nodemon itself, with a custom task to wrap it
that does the same work as grunt-nodemon was doing.

CHANGELOG.md

@@ -36,6 +36,7 @@ Runtime
  - Skip loading node html if disableEditor set #2684
  - Update util.writeFile to write to tmp file before rename #2683
  - Fix getModuleFiles function to include path property #2705 (@t-kawamorita)
+ - Update nodemon to latest so grunt dev task behaves
 
 Nodes
 

Gruntfile.js

@@ -20,7 +20,7 @@ var sass = require("node-sass");
 
 module.exports = function(grunt) {
 
-    var nodemonArgs = ["-v"];
+    var nodemonArgs = ["-V"];
     var flowFile = grunt.option('flowFile');
     if (flowFile) {
         nodemonArgs.push(flowFile);
@@ -507,7 +507,6 @@ module.exports = function(grunt) {
     grunt.loadNpmTasks('grunt-contrib-watch');
     grunt.loadNpmTasks('grunt-concurrent');
     grunt.loadNpmTasks('grunt-sass');
-    grunt.loadNpmTasks('grunt-nodemon');
     grunt.loadNpmTasks('grunt-contrib-compress');
     grunt.loadNpmTasks('grunt-contrib-copy');
     grunt.loadNpmTasks('grunt-chmod');
@@ -521,6 +520,25 @@ module.exports = function(grunt) {
     grunt.loadNpmTasks('grunt-npm-command');
     grunt.loadNpmTasks('grunt-mkdir');
 
+    grunt.registerMultiTask('nodemon', 'Runs a nodemon monitor of your node.js server.', function () {
+        const nodemon = require('nodemon');
+        this.async();
+        const options = this.options();
+        options.script = this.data.script;
+        let callback;
+        if (options.callback) {
+            callback = options.callback;
+            delete options.callback;
+        } else {
+            callback = function(nodemonApp) {
+                nodemonApp.on('log', function (event) {
+                    console.log(event.colour);
+                });
+            };
+        }
+        callback(nodemon(options));
+    });
+
     grunt.registerMultiTask('attachCopyright', function() {
         var files = this.data.src;
         var copyright = "/**\n"+

package.json

@@ -99,7 +99,6 @@
         "grunt-jsonlint": "2.1.3",
         "grunt-mkdir": "~1.0.0",
         "grunt-mocha-istanbul": "5.0.2",
-        "grunt-nodemon": "~0.4.2",
         "grunt-npm-command": "~0.1.2",
         "grunt-sass": "~3.1.0",
         "grunt-simple-mocha": "~0.4.1",
@@ -112,6 +111,7 @@
         "mosca": "^2.8.3",
         "node-red-node-test-helper": "^0.2.5",
         "node-sass": "^4.14.1",
+        "nodemon": "2.0.4",
         "should": "13.2.3",
         "sinon": "1.17.7",
         "stoppable": "^1.1.0",