Bump robinraju/release-downloader from 1.7 to 1.8

Bumps [robinraju/release-downloader](https://github.com/robinraju/release-downloader) from 1.7 to 1.8.
- [Release notes](https://github.com/robinraju/release-downloader/releases)
- [Commits](robinraju/release-downloader@v1.7...v1.8)

---
updated-dependencies:
- dependency-name: robinraju/release-downloader
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

action.yml

@@ -22,7 +22,7 @@ runs:
         otp-version: 25.3
         install-hex: true
         version-type: strict
-    - uses: robinraju/release-downloader@v1.7
+    - uses: robinraju/release-downloader@v1.8
       with:
         repository: 'jshmrtn/mix-dependency-submission'
         tag: "v1.0.0-beta.1"