fix: add sbt/setup-sbt for the dependency graph workflow (scala#22228)

IT turns out that
https://github.com/scalacenter/sbt-dependency-submission doesn't include
sbt if it's missing

Related to scala#22224

[skip ci]

Author: hamzaremmal

.github/workflows/dependency-graph.yml

@@ -9,6 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: sbt/setup-sbt@v1
       - uses: scalacenter/sbt-dependency-submission@v3
         env:
           DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}