Rename workflow file

Because build is a bad name for a workflow that doesn't build anything

.forgejo/workflows/build.yaml

@@ -1,33 +0,0 @@
----
-on: [push]
-
-name: CI
-
-jobs:
-  formatting:
-    name: Formatting
-    runs-on: ubuntu-22.04
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Set up Rust
-        uses: https://github.com/dtolnay/rust-toolchain@nightly
-        with:
-          components: rustfmt
-      - name: Check Rust formatting
-        run: cargo fmt --all -- --check
-
-  clippy:
-    name: Clippy
-    runs-on: ubuntu-22.04
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Set up Rust
-        uses: https://github.com/dtolnay/rust-toolchain@nightly
-        with:
-          components: clippy
-      - name: Install dependencies
-        uses: ./.forgejo/actions/install-system-libraries
-      - name: Run Clippy
-        run: cargo clippy -- -D warnings