Drop 7.3 prefer-lowest

Author: andrewnicols

.github/workflows/ci.yml

@@ -18,9 +18,6 @@ jobs:
             matrix:
                 php: [ '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
                 dependency-version: [ '' ]
-                include:
-                    -   php: '7.3'
-                        dependency-version: '--prefer-lowest'
         steps:
             -   name: Checkout
                 uses: actions/checkout@v4