chore: pin docker action

this was accidentally left unpinned

Author: smlx

.github/workflows/release.yaml

@@ -38,7 +38,7 @@ jobs:
     - uses: actions/setup-go@4dc6199c7b1a012772edbd06daecab0f50c9053c # v6.1.0
       with:
         go-version: stable
-    - uses: docker/setup-buildx-action@v3
+    - uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3.12.0
     - name: Login to GHCR
       uses: docker/login-action@5e57cd118135c172c3672efd75eb46360885c0ef # v3.6.0
       with: