delete generate workflow which uses old gh-pages branch

Author: koron

.github/workflows/generate.yml

@@ -9,10 +9,6 @@ jobs:
     steps:
       - name: Enable each workflow
         run: |
-          curl -i -X PUT \
-            -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
-            -H "Accept: application/vnd.github.v3+json" \
-               'https://api.github.com/repos/vim-jp/vimdoc-en/actions/workflows/generate.yml/enable'
           curl -i -X PUT \
             -H 'Authorization: token ${{ secrets.GITHUB_TOKEN }}' \
             -H "Accept: application/vnd.github.v3+json" \