.github/workflows/codeql.yml: try ubuntu-20.04

- also be explicit about just "c"

Author: robohack

.github/workflows/codeql.yml

@@ -25,7 +25,7 @@ jobs:
     #   - https://gh.io/supported-runners-and-hardware-resources
     #   - https://gh.io/using-larger-runners (GitHub.com only)
     # Consider using larger runners or machines with greater resources for possible analysis time improvements.
-    runs-on: ${{ (matrix.language == 'swift' && 'macos-latest') || 'ubuntu-latest' }}
+    runs-on: ${{ (matrix.language == 'swift' && 'macos-latest') || 'ubuntu-20.04' }}
     timeout-minutes: ${{ (matrix.language == 'swift' && 120) || 360 }}
     permissions:
       # required for all workflows
@@ -42,7 +42,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
-        - language: c-cpp
+        - language: c
           build-mode: manual
         # CodeQL supports the following values keywords for 'language': 'c-cpp', 'csharp', 'go', 'java-kotlin', 'javascript-typescript', 'python', 'ruby', 'swift'
         # Use `c-cpp` to analyze code written in C, C++ or both