ci: Update to codeql-action v3

Silences a harmless deprecation warning.

.github/workflows/check.yml

@@ -178,7 +178,7 @@ jobs:
  steps:
  # Initializes the CodeQL tools for scanning.
  - name: Initialize CodeQL
- uses: github/codeql-action/init@v2
+ uses: github/codeql-action/init@v3
  with:
  languages: ${{ matrix.language }}
  # If you wish to specify custom queries, you can do so here or in a config file.
@@ -211,7 +211,7 @@ jobs:
  # Can't use `meson compile` here because Ubuntu 20.04 is too old
  run: ninja -C _build
  - name: Perform CodeQL Analysis
- uses: github/codeql-action/analyze@v2
+ uses: github/codeql-action/analyze@v3
 
  valgrind:
  name: Run tests in valgrind