deps(actions): bump erlef/setup-beam from 1.17.5 to 1.20.4

Bumps [erlef/setup-beam](https://github.com/erlef/setup-beam) from 1.17.5 to 1.20.4.
- [Release notes](https://github.com/erlef/setup-beam/releases)
- [Commits](erlef/setup-beam@2f0cc07...e6d7c94)

---
updated-dependencies:
- dependency-name: erlef/setup-beam
  dependency-version: 1.20.4
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/hypatia-scan.yml

@@ -25,7 +25,7 @@ jobs:
           fetch-depth: 0  # Full history for better pattern analysis
 
       - name: Setup Elixir for Hypatia scanner
-        uses: erlef/setup-beam@2f0cc07b4b9bea248ae098aba9e1a8a1de5ec24c # v1.18.2
+        uses: erlef/setup-beam@e6d7c94229049569db56a7ad5a540c051a010af9 # v1.18.2
         with:
           elixir-version: '1.19.4'
           otp-version: '28.3'