[llvm] [GitHub][CI] Add clang-tidy premerge workflow (PR #154829)

[Baranov Victor via llvm-commits]

================
@@ -0,0 +1,126 @@
+name: "Code lint"
+
+permissions:
+  contents: read
+
+on:
+  pull_request:
+    branches:
+      - main
+      - 'users/**'
+    paths:
+      - 'clang-tools-extra/clang-tidy/**'
+
+jobs:
+  code_linter:
+    if: github.repository_owner == 'llvm'
+    runs-on: ubuntu-24.04
+    defaults:
+      run:
+        shell: bash
----------------
vbvictor wrote:

I only left `source <(git diff --name-only HEAD~1...HEAD | python3 .ci/compute_projects.py)` as is because it's the same in `code-formatting` job. I'd refactor it in follow-up to be `. <(...)`

https://github.com/llvm/llvm-project/pull/154829