Introduce pre-commit & GitHub Actions for it

Change-Id: I4604d13e5ccf74ec4c7088a40a9f7f915f9b1293

.github/workflows/build/action.yml

@@ -0,0 +1,13 @@
+name: build
+
+runs:
+    using: composite
+
+    steps:
+    - name: Install dependencies
+      shell: bash
+      run: pip install pre-commit
+
+    - name: Lint
+      shell: bash
+      run: pre-commit run --all

.github/workflows/gerrit.yml

@@ -0,0 +1,38 @@
+name: gerrit checks
+
+on:
+  workflow_dispatch:
+    inputs:
+      ref:
+        type: string
+      gerrit-ref:
+        type: string
+      change:
+        type: string
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: lineageos-infra/fetch-gerrit-change@main
+      with:
+        gerrit-ref: ${{ inputs.gerrit-ref }}
+        ref: ${{ inputs.ref }}
+
+    - name: Check if build/action.yml exists
+      id: check
+      run: |
+        if [ -f ./.github/workflows/build/action.yml ]; then
+          echo "run=1" >> "$GITHUB_OUTPUT"
+        fi
+
+    - name: Build
+      if: ${{ steps.check.outputs.run }}
+      uses: ./.github/workflows/build
+
+    - uses: lineageos-infra/gerrit-vote@main
+      if: ${{ steps.check.outputs.run && always() }}
+      with:
+        auth: ${{ secrets.GERRIT_VOTE_CREDS }}
+        change: ${{ inputs.change }}
+        ref: ${{ inputs.ref }}

.pre-commit-config.yaml

@@ -0,0 +1,15 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v6.0.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-added-large-files
+  - repo: https://github.com/macisamuele/language-formatters-pre-commit-hooks
+    rev: v2.15.0
+    hooks:
+      - id: pretty-format-kotlin
+        args: [--autofix, --ktfmt, --ktfmt-style=kotlinlang]