Try adding keytar to store credentials

.travis.yml

@@ -5,3 +5,4 @@ node_js:
   - '12'
 before_install:
   - npm install -g grunt-cli
+  - sudo apt-get -y install libsecret-1-dev

package.json

@@ -45,6 +45,7 @@
 	"dependencies": {
 		"grunt": "^1.0.3",
 		"inquirer": "^5.1.0",
+		"keytar": "^5.1.0",
 		"request": "^2.83.0",
 		"xmlrpc": "^1.3.1"
 	},

tasks/patch_wordpress.js

@@ -13,6 +13,7 @@ const exec = require( 'child_process' ).exec;
 const execSync = require( 'child_process' ).execSync;
 const spawn = require( 'child_process' ).spawn;
 const inquirer = require( 'inquirer' );
+const keytar = require( 'keytar' );
 const url = require( 'url' );
 const fs = require( 'fs' );
 const trac = require( '../lib/trac.js' );
@@ -335,17 +336,26 @@ module.exports = function( grunt ) {
 				);
 			} );
 		};
-		if ( process.env.WPORG_USERNAME && process.env.WPORG_PASSWORD ) {
-			uploadPatchWithCredentials( process.env.WPORG_USERNAME, process.env.WPORG_PASSWORD );
-		} else {
-			inquirer.prompt(
-				[
-					{ type: 'input', name: 'username', message: 'Enter your WordPress.org username' },
-					{ type: 'password', name: 'password', message: 'Enter your WordPress.org password' },
-				] ).then( ( answers ) => {
-				uploadPatchWithCredentials( answers.username, answers.password );
+		const getCredentials = keytar.findCredentials( 'wporg_patch' );
+		getCredentials.then( ( savedCredentials ) => {
+			if ( savedCredentials.length > 0 ) {
+				uploadPatchWithCredentials( savedCredentials[ 0 ].account, savedCredentials[ 0 ].password );
+			} else if ( process.env.WPORG_USERNAME && process.env.WPORG_PASSWORD ) {
+				uploadPatchWithCredentials( process.env.WPORG_USERNAME, process.env.WPORG_PASSWORD );
+			} else {
+				inquirer.prompt(
+					[
+						{ type: 'input', name: 'username', message: 'Enter your WordPress.org username' },
+						{ type: 'password', name: 'password', message: 'Enter your WordPress.org password' },
+						{ type: 'confirm', name: 'saveCredentials', message: 'Save your credentials?' },
+					] ).then( ( answers ) => {
+					uploadPatchWithCredentials( answers.username, answers.password );
+					if ( answers.saveCredentials ) {
+						keytar.setPassword( 'wporg_patch', answers.username, answers.password );
+					}
+				}
+				);
 			}
-			);
-		}
+		} );
 	} );
 };