publish on rubygems.org instead of Github

Github Package Repository doesn't allow anonymous download of public gems,
this is useless for us as we need to be able to download the gem from
everywhere by anyone.

.github/workflows/release.yaml

@@ -29,7 +29,7 @@ jobs:
       - name: Publish gem to Github Package Repository
         uses: addnab/docker-run-action@v3
         env:
-          GEM_HOST_API_KEY: "Bearer ${{secrets.GITHUB_TOKEN}}"
+          GEM_HOST_API_KEY: "Bearer ${{secrets.RUBYGEM_PUSH_KEY}}"
           OWNER: ${{ github.repository_owner }}
         with:
           image: linuxfrorg/board-sse-linuxfr.org:${{ github.sha }}
@@ -43,5 +43,5 @@ jobs:
             mkdir -p "${HOME}/.gem"
             touch "${HOME}/.gem/credentials"
             chmod 0600 "${HOME}/.gem/credentials"
-            printf -- "---\n:github: ${GEM_HOST_API_KEY}\n" > "${HOME}/.gem/credentials"
-            gem push --KEY github --host "https://rubygems.pkg.github.com/${OWNER}" *.gem
+            printf -- "---\n:rubygem: ${GEM_HOST_API_KEY}\n" > "${HOME}/.gem/credentials"
+            gem push --KEY rubygem *.gem