Remove Ubuntu 20.04 (#1048)

* Remove Ubuntu 20.04

GitHub/Microsoft no longer provides ubuntu-20.04 testing.

* Also remove Win2019

Win2019 is soon to go away.

.github/workflows/ci.yml

@@ -16,7 +16,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
           - os: ubuntu-22.04
           - os: ubuntu-22.04-arm
           - os: ubuntu-24.04
@@ -55,7 +54,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: windows-2019
           - os: windows-2022
           - os: windows-2025
 
@@ -90,7 +88,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
           - os: ubuntu-22.04
           - os: ubuntu-22.04-arm
           - os: ubuntu-24.04
@@ -127,7 +124,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: windows-2019
           - os: windows-2022
           - os: windows-2025
 
@@ -187,7 +183,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
           - os: ubuntu-22.04
           - os: ubuntu-22.04-arm
           - os: ubuntu-24.04
@@ -224,7 +219,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: windows-2019
           - os: windows-2022
           - os: windows-2025