Bump @slack/web-api from 7.13.0 to 7.15.0

Bumps [@slack/web-api](https://github.com/slackapi/node-slack-sdk) from 7.13.0 to 7.15.0.
- [Release notes](https://github.com/slackapi/node-slack-sdk/releases)
- [Commits](https://github.com/slackapi/node-slack-sdk/compare/@slack/web-api@7.13.0...@slack/web-api@7.15.0)

---
updated-dependencies:
- dependency-name: "@slack/web-api"
  dependency-version: 7.15.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Closes #141

Change-Id: I48d8059201a2ce2c9dff5ad23cfb8a4acd01a975
diff --git a/package.json b/package.json
index 739cdc2..3733794 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
   "author": "Marc Kupietz",
   "license": "APACHE-2.0",
   "dependencies": {
-    "@slack/web-api": "^7.13.0",
+    "@slack/web-api": "^7.15.0",
     "axios": "^1.7.9",
     "chai": "^6.2.2",
     "form-data": "^4.0.5",