Remove custome_container for building the docs (#4198)

Author: albertvillanova

.github/workflows/build_documentation.yml

@@ -14,6 +14,5 @@ jobs:
       commit_sha: ${{ github.sha }}
       package: trl
       version_tag_suffix: ""
-      custom_container: huggingface/transformers-doc-builder
     secrets:
       hf_token: ${{ secrets.HF_DOC_BUILD_PUSH }}

.github/workflows/build_pr_documentation.yml

@@ -16,4 +16,3 @@ jobs:
       pr_number: ${{ github.event.number }}
       package: trl
       version_tag_suffix: ""
-      custom_container: huggingface/transformers-doc-builder