delete the GitHub-hosted workflows the native gate replaces

main.yml (lint, generate-check, build+test), go-cross.yml (ubuntu/macos/windows
matrix) and release.yml (goreleaser) all ran on GitHub's machines. main.yml was
also half dead: it triggers on a push to master and this repo's branch is main,
so only its pull_request half ever fired. The suite now runs in hanzo.yml on
the git.hanzo.ai fleet.

.github/workflows/release.yml

@@ -1,34 +0,0 @@
-name: Release
-
-on:
-  push:
-    tags:
-      - v[0-9]+.[0-9]+*
-
-env:
-  GO_VERSION: stable
-
-jobs:
-
-  release:
-    name: Create a release
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Check out code
-        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
-        with:
-          fetch-depth: 0
-
-      - name: Set up Go ${{ env.GO_VERSION }}
-        uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5.6.0
-        with:
-          go-version: ${{ env.GO_VERSION }}
-
-      - name: Run GoReleaser
-        uses: goreleaser/goreleaser-action@5742e2a039330cbb23ebf35f046f814d4c6ff811 # v5.1.0
-        with:
-          version: latest
-          args: release --clean
-        env:
-          GITHUB_TOKEN: ${{ secrets.GH_TOKEN_REPO }}