fixup! WIP try old compilers with newer ubuntu

Author: robUx4

.github/workflows/linux.yaml

@@ -48,7 +48,7 @@ jobs:
         run: cmake --install _build --prefix ${GITHUB_WORKSPACE}/_built
 
   GCC-7:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-20.04
     env:
       CMAKE_OPTIONS: -DDEV_MODE=ON -DBUILD_TESTING=ON
       CMAKE_MATROSKA_OPTIONS: -DBUILD_EXAMPLES=ON
@@ -89,7 +89,7 @@ jobs:
         run: cmake --install _build --prefix ${GITHUB_WORKSPACE}/_built
 
   Clang-7:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-20.04
     env:
       CMAKE_OPTIONS: -DDEV_MODE=ON -DBUILD_TESTING=ON
       CMAKE_MATROSKA_OPTIONS: -DBUILD_EXAMPLES=ON