chore(ci): remove auto-assign

this mostly doesn't work anyway

.github/workflows/assign.yml

@@ -1,18 +0,0 @@
-name: Auto-assign project
-
-on:
-  issues:
-    types: [opened]
-  pull_request:
-    types: [opened]
-env:
-  MY_GITHUB_TOKEN: ${{ secrets.GH_PAT }}
-
-jobs:
-  assign:
-    runs-on: ubuntu-latest
-    name: Assign Project and Milestone
-    steps:
-    - uses: srggrs/assign-one-project-github-action@1.3.1
-      with:
-        project: 'https://github.com/orgs/goreleaser/projects/3'