Bump @actions/core from 1.2.4 to 1.2.6 (#158)

Bumps [@actions/core](https://github.com/actions/toolkit/tree/HEAD/packages/core) from 1.2.4 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)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -31,7 +31,7 @@
   "author": "shimataro",
   "license": "MIT",
   "dependencies": {
-    "@actions/core": "1.2.4"
+    "@actions/core": "1.2.6"
   },
   "devDependencies": {
     "@types/node": "14.0.27",