Bump gittuf/gittuf-installer from 0.5.2 to 0.6.0 (#56)

Bumps [gittuf/gittuf-installer](https://github.com/gittuf/gittuf-installer) from 0.5.2 to 0.6.0.
- [Release notes](https://github.com/gittuf/gittuf-installer/releases)
- [Commits](gittuf/gittuf-installer@5c0fb4a...226868d)

---
updated-dependencies:
- dependency-name: gittuf/gittuf-installer
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/gittuf-rsl-main.yml

@@ -12,7 +12,7 @@ jobs:
       id-token: write
     steps:
       - name: Install gittuf
-        uses: gittuf/gittuf-installer@5c0fb4a2a0dc9434598cf2e74bb601d76861fc97
+        uses: gittuf/gittuf-installer@226868d1502eb509afafcf3c6722573785d6e013
       - name: Install gitsign
         uses: chainguard-dev/actions/setup-gitsign@main
       - name: Checkout repository

.github/workflows/gittuf-rsl-non-main.yml

@@ -12,7 +12,7 @@ jobs:
       id-token: write
     steps:
       - name: Install gittuf
-        uses: gittuf/gittuf-installer@5c0fb4a2a0dc9434598cf2e74bb601d76861fc97
+        uses: gittuf/gittuf-installer@226868d1502eb509afafcf3c6722573785d6e013
       - name: Install gitsign
         uses: chainguard-dev/actions/setup-gitsign@main
       - name: Checkout repository

.github/workflows/gittuf-verify.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Install gittuf
-        uses: gittuf/gittuf-installer@5c0fb4a2a0dc9434598cf2e74bb601d76861fc97
+        uses: gittuf/gittuf-installer@226868d1502eb509afafcf3c6722573785d6e013
       - name: Checkout and verify repository
         run: |
           gittuf clone https://github.com/${{ github.repository }}