fix(ci): build Linux binaries on Ubuntu 20.04 for broader GLIBC compatibility

.github/workflows/binaries.yml

@@ -15,9 +15,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
+        os: [ubuntu-20.04, windows-latest, macos-latest]
         include:
-          - os: ubuntu-latest
+          - os: ubuntu-20.04
             artifact_name: voxvera-linux
             asset_name: voxvera-linux
           - os: windows-latest