ci: Remove Windows-2019 case, those runners are about to be removed by GH

Signed-off-by: Larry Gritz <lg@larrygritz.com>

Author: lgritz

.github/workflows/ci.yml

@@ -612,24 +612,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - desc: Windows-2019 VS2019
-            runner: windows-2019
-            nametag: windows-2019
-            generator: "Visual Studio 16 2019"
-            python_ver: "3.9"
-            opencolorio_ver: v2.3.2
-            openexr_ver: v3.3.2
-            openimageio_ver: release
-            skip_tests: 1
-            setenvs: export LLVM_VERSION=18.1.8
-                            OSL_CMAKE_FLAGS="-DUSE_LLVM_BTCODE=ON"
-                            PUGIXML_VERSION=v1.14
-                            OpenImageIO_BUILD_MISSING_DEPS="Freetype;TIFF;libdeflate;libjpeg-turbo"
-
-          #
-          # Windows 2022 / MSVS 17 case is below. It's not working yet,
-          # work in progress.
-          #
           - desc: Windows-2022 VS2022
             runner: windows-2022
             nametag: windows-2022