gha: remove windows-2019 from installer matrix

2019 installer is not needed and each entry of the matrix triggers a
separate e2e workflow. So it is good to only have a 1x1 matrix.

Author: Jakub Sliacan

.github/workflows/windows-installer.yml

@@ -11,7 +11,6 @@ jobs:
       fail-fast: false
       matrix:
         os:
-          - windows-2019
           - windows-2022
         go:
           - '1.20'