Auto label PRs that may require extra checks (#2785)

Add a new workflow that automatically adds the label "Z-BenchCI" to PRs that touch compiler, toolchain, dependencies and driver files that invoke our dependencies.

I also removed the label from the toolchain update job since this workflow will add the label once the PR is created.

.github/labeler.yml

@@ -0,0 +1,16 @@
+# Copyright Kani Contributors
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+#
+# Configuration for auto-labeling PRs
+#
+# Note that we enable dot, so "**" matches all files in a folder
+
+Z-BenchCI:
+ - kani-compiler/**
+ - rust-toolchain.toml
+ - kani-dependencies
+ - kani-driver/src/call-*
+ - Cargo.lock
+ - cprover_bindings/**
+ - library/**
+

.github/workflows/labeler.yml

@@ -0,0 +1,30 @@
+# Copyright Kani Contributors
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+#
+# Auto label PRs based on the files that were changed
+#
+# This PR runs on `pull_request_target` because it needs extra write permission.
+#
+# Thus, we keep this workflow minimal, and the only action used here is from a
+# verified publisher.
+#
+# See <https://github.com/actions/labeler/issues/121> for more details.
+
+name: Auto Label
+on: pull_request_target
+
+jobs:
+ auto-label:
+ permissions:
+ contents: read
+ pull-requests: write
+ runs-on: ubuntu-latest
+ steps:
+ - name: Checkout Kani
+ uses: actions/checkout@v3
+
+ - name: Label PR
+ uses: actions/labeler@v4
+ with:
+ dot: true
+

.github/workflows/toolchain-upgrade.yml

@@ -74,7 +74,6 @@ jobs:
  branch: toolchain-${{ env.next_toolchain_date }}
  delete-branch: true
  title: 'Automatic toolchain upgrade to nightly-${{ env.next_toolchain_date }}'
- labels: Z-BenchCI
  body: >
  Update Rust toolchain from nightly-${{ env.current_toolchain_date }} to
  nightly-${{ env.next_toolchain_date }} without any other source changes.