[GH Actions] Removed ubuntu-20.04 runners (#32)

Author: DownerCase

.github/workflows/build-ubuntu.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         library_type: [static, shared, object]
-        os: [ubuntu-24.04, ubuntu-22.04, ubuntu-20.04]
+        os: [ubuntu-24.04, ubuntu-22.04]
 
     # The CMake configure and build commands are platform agnostic and should work equally well on Windows or Mac.
     # You can convert this to a matrix build if you need cross-platform coverage.
@@ -136,4 +136,4 @@ jobs:
     - name: Run integration test (Debug)
       run: ./integration_test
       working-directory: ${{ github.workspace }}/samples/integration_test/_build/debug
-      if: ${{ matrix.library_type != 'object' }}
+      if: ${{ matrix.library_type != 'object' }}