Revert "Use default compiler (GCC 11) on coverage run to be compatible with lcov version"

This reverts commit df7097d56e.

.github/workflows/osrm-backend.yml

@@ -145,7 +145,7 @@ jobs:
     strategy:
       matrix:
         include:
-          - name: gcc-11-debug-cov
+          - name: gcc-13-debug-cov
             continue-on-error: false
             node: 20
             runs-on: ubuntu-22.04
@@ -153,7 +153,7 @@ jobs:
             BUILD_TYPE: Debug
             CCOMPILER: gcc-13
             CUCUMBER_TIMEOUT: 20000
-            CXXCOMPILER: g++-11
+            CXXCOMPILER: g++-13
             ENABLE_COVERAGE: ON
 
           - name: gcc-13-debug-asan-ubsan