Bump @actions/core from 1.2.3 to 1.2.6 in /shopify-theme-api

Bumps [@actions/core](https://github.com/actions/toolkit/tree/HEAD/packages/core) from 1.2.3 to 1.2.6.
- [Release notes](https://github.com/actions/toolkit/releases)
- [Changelog](https://github.com/actions/toolkit/blob/main/packages/core/RELEASES.md)
- [Commits](https://github.com/actions/toolkit/commits/HEAD/packages/core)

Signed-off-by: dependabot[bot] <support@github.com>

shopify-theme-api/package.json

@@ -5,7 +5,7 @@
   "main": "dist/index.js",
   "private": true,
   "dependencies": {
-    "@actions/core": "^1.2.3",
+    "@actions/core": "^1.2.6",
     "shopify-api-node": "^3.3.0"
   },
   "devDependencies": {