chore: hardcode SHA and bump to v4.6.0 instead

Author: jgravois

.github/workflows/deploy.yml

@@ -115,7 +115,7 @@ jobs:
         run: echo "${{ github.sha }}" >> benefits/static/sha.txt
 
       - name: Docker Login to GitHub Container Registry
-        uses: docker/login-action@v4.5.2
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}