ubuntu-20.04 is deprecated

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
       CT2_VERBOSE: 1
     strategy:
       matrix:
-        os: [ubuntu-20.04]
+        os: [ubuntu-latest]
         backend: [mkl, dnnl]
 
     steps:
@@ -74,7 +74,7 @@ jobs:
 
 
   build-and-test-cpp-aarch64:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     env:
       CT2_VERBOSE: 1
     strategy:
@@ -132,10 +132,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-20.04, windows-2019]
+        os: [ubuntu-latest, windows-2019]
         arch: [auto64]
         include:
-        - os: ubuntu-20.04
+        - os: ubuntu-latest
           arch: aarch64
         - os: macos-13
           arch: arm64
@@ -181,7 +181,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-20.04, windows-2019]
+        os: [ubuntu-latest, windows-2019]
 
     steps:
       - name: Set up Python 3.9
@@ -255,7 +255,7 @@ jobs:
   publish-python-wheels-on-pypi:
     if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
     needs: [build-and-test-cpp-x86_64, build-python-wheels, test-python-wheels, check-python-style]
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     steps:
       - name: Download Python wheels
@@ -274,7 +274,7 @@ jobs:
 
 
   build-and-push-docker-images:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
         with: