Release: v1.2.3 (#316)

## What's Changed
* chore: update dependencies (automated) by @verbanicm in
#312
* Relax app.yml detection to just "runtime" by @sethvargo in
#313
* Switch to pull non-secret values from env by @sethvargo in
#314


**Full Changelog**:
v1.2.2...3f82be1

Author: google-github-actions-bot

dist/index.js

@@ -1,6 +1,6 @@
 {
   "name": "deploy-appengine",
-  "version": "1.2.2",
+  "version": "1.2.3",
   "description": "Github Action: Deploy to Google App Engine",
   "main": "dist/index.js",
   "scripts": {