CI: Update new GH env, add PHP versions up to 8.3

.gitattributes

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+.gitattributes export-ignore
+.gitignore export-ignore
+.github export-ignore
+phpstan.neon export-ignore

.github/workflows/code-analysis.yaml

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+name: Code analysis
+
+on:
+  push:
+  pull_request:
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  static-analysis:
+    strategy:
+      fail-fast: false
+      matrix:
+        php:
+          - "7.2"
+          - "7.3"
+          - "7.4"
+          - "8.0"
+          - "8.1"
+          - "8.2"
+          - "8.3"
+    name: PHPStan at PHP ${{ matrix.php }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+
+      - name: Get Composer cache directory
+        id: composer-cache
+        run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
+
+      - name: Cache dependencies
+        uses: actions/cache@v3
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('composer.json') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install Composer dependencies
+        run: composer update --no-progress
+
+      - name: Statically analyze code (PHPStan)
+        run: composer run phpstan -- --ansi