Update OS matrix to reflect only systems from the past 3 years

Author: mattrbeck

.github/workflows/ci.yml

@@ -12,11 +12,12 @@ jobs:
       matrix:
         os:
           - ubuntu-latest
+          - ubuntu-24.04
           - ubuntu-22.04
-          - ubuntu-20.04
           - macos-latest
-          - macos-12
-          - macos-11
+          - macos-15
+          - macos-14
+          - macos-13
           # - windows-latest
     runs-on: ${{matrix.os}}
     env: