[Github] Improve automatic new issue labelling (#65309)

This patch:
* Replaces `andymckay/labeler` which does not appear to be maintained by
github official solution
* Removes the closed issue workflow which was disabled a few years ago
and never fixed.
* Adds a few rules to add label based on PR title, hopefully that can
make triaging simpler. If that turns out to be useful, we can consider
adding more rules for backends, etc. We could technically also pattern
match the body of the issue but I'm concerned about trying to be _too_
clever.

The new system is only triggered on PR open so manual labels should not
be removed.

.github/workflows/closed-issues.yml

@@ -1,20 +0,0 @@
-name: Labeling closed issues
-on:
-  workflow_dispatch
-#  issues:
-#    types: ['closed']
-
-permissions:
-  contents: read
-
-jobs:
-  automate-issues-labels:
-    permissions:
-      issues: write  # for andymckay/labeler to label issues
-      pull-requests: write  # for andymckay/labeler to label PRs
-    runs-on: ubuntu-latest
-    if: github.repository == 'llvm/llvm-project'
-    steps:
-      - uses: andymckay/labeler@1.0.4
-        with:
-          remove-labels: 'awaiting-review'

.github/workflows/new-issues-labeler.yml

@@ -0,0 +1,32 @@
+'new issue':
+  - '/.*/'
+
+'clang':
+  - '/\bclang(?!\-)\b/i'
+
+'clang-format':
+  - '/\bclang-format/i'
+
+'clang-tidy':
+  - '/\bclang-tidy/i'
+
+'libc++':
+  - '/libc[+x]{2}(?!\-)/i'
+
+'libc++-abi':
+  - '/libc[+x]{2}-abi/i'
+
+'libc':
+  - '/\blibc(?![-+])\b/i'
+
+'flang':
+  - '/\bflang(?!\-)\b/i'
+
+'lld':
+  - '/\blld(?!\-)\b/i'
+
+'mlir':
+  - '/\bmlir(?!\-)\b/i'
+
+'bolt':
+  - '/\bbolt(?!\-)\b/i'

.github/workflows/new-issues.yml

@@ -9,12 +9,15 @@ permissions:
 jobs:
   automate-issues-labels:
     permissions:
-      issues: write  # for andymckay/labeler to label issues
-      pull-requests: write  # for andymckay/labeler to label PRs
+      issues: write
     runs-on: ubuntu-latest
     if: github.repository == 'llvm/llvm-project'
     steps:
-      - uses: andymckay/labeler@1.0.4
+      - uses: github/issue-labeler@v3.2
         with:
-          add-labels: 'new issue'
-          ignore-if-labeled: true
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          configuration-path: .github/workflows/new-issues-labeler.yml
+          include-title: 1
+          include-body: 0
+          sync-labels: 0
+          enable-versioned-regex: 0