chore: add RF 7.3 to github workflow for testing

Author: d-biehl

.github/workflows/build-test-package-publish.yml

@@ -33,7 +33,7 @@ jobs:
       matrix:
         os: [macos-latest, ubuntu-latest, windows-latest]
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
-        robot-version: ["rf41", "rf50", "rf60", "rf61", "rf70", "rf71", "rf72"]
+        robot-version: ["rf41", "rf50", "rf60", "rf61", "rf70", "rf71", "rf72", "rf73"]
         exclude:
           - os: macos-latest
             python-version: "3.8"