fix(@schematics/angular): add text-summary to code coverage reporter

Author: kasaharu

packages/schematics/angular/library/files/karma.conf.js.template

@@ -17,7 +17,7 @@ module.exports = function (config) {
     },
     coverageIstanbulReporter: {
       dir: require('path').join(__dirname, '<%= relativePathToWorkspaceRoot %>/coverage/<%= folderName %>'),
-      reports: ['html', 'lcovonly'],
+      reports: ['html', 'lcovonly', 'text-summary'],
       fixWebpackSourcePaths: true
     },
     reporters: ['progress', 'kjhtml'],