ci: bump CodeQL Action version from v3 to v4

Closes #790.

.github/workflows/codeql.yml

@@ -44,7 +44,7 @@ jobs:
           sudo apt-get install --yes libreadline-dev
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v3
+        uses: github/codeql-action/init@v4
         with:
           languages: ${{ matrix.language }}
           config-file: ./.github/codeql/config.yml
@@ -59,6 +59,6 @@ jobs:
           make -sj2 || echo '*** Ignoring build failure for CodeQL ***'
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v3
+        uses: github/codeql-action/analyze@v4
         with:
           category: "/language:${{ matrix.language }}"