Remove gitbook workflow

.github/workflows/gitbook.yaml

@@ -1,29 +0,0 @@
-name: Gitbook
-
-on:
-  push:
-
-jobs:
-  gitbook:
-    name: Gitbook
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v3
-        with:
-          submodules: true
-
-      - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          components: rustfmt, clippy
-
-      - name: Install project tools
-        uses: ok-nick/setup-aftman@v0.3.0
-
-      - name: Generate Gitbook
-        run: just generate-gitbook
-
-      - name: Publish Gitbook
-        run: just publish-gitbook