[skip ci] change docker image tag for e2e tests

.github/workflows/e2e-tests.yml

@@ -14,11 +14,9 @@ jobs:
     uses: './.github/workflows/publish-image.yml'
     secrets: inherit
     with:
-      # FIXME: e2e tests has default docker image tag "main" - https://github.com/blockscout/blockscout-ci-cd/blob/56a5424cfa07b03ca378e04650c4c67650ec40a0/charts/blockscout-stack/values/e2e/values.yaml#L352
       # NOTE: by default the image will be built with type=ref,event=tag; so we don't need to specify it here
       tags: |
-        type=raw,value=main
-        type=ref,event=branch
+        type=raw,value=e2e
 
   deploy_e2e:
     name: Deploy E2E instance