remove broken flakestry github action

This has been throwing http 500 for a while.

.github/workflows/publish.yml

@@ -1,22 +0,0 @@
-name: "Publish a flake to flakestry"
-on:
-    push:
-        tags:
-        - "v?[0-9]+.[0-9]+.[0-9]+"
-        - "v?[0-9]+.[0-9]+"
-    workflow_dispatch:
-        inputs:
-            tag:
-                description: "The existing tag to publish"
-                type: "string"
-                required: true
-jobs:
-    publish-flake:
-        runs-on: ubuntu-latest
-        permissions:
-            id-token: "write"
-            contents: "read"
-        steps:
-            - uses: flakestry/flakestry-publish@main
-              with:
-                version: "${{ inputs.tag || github.ref_name }}"