Merge pull request #6900 from alphagov/dependabot/github_actions/github/accessibility-alt-text-bot-1.7.3

Bump github/accessibility-alt-text-bot from 1.7.2 to 1.7.3

Author: owenatgov

.github/workflows/accessibility-bot.yml

@@ -28,4 +28,4 @@ jobs:
 
     steps:
       - name: Check images for alt text
-        uses: github/accessibility-alt-text-bot@v1.7.2
+        uses: github/accessibility-alt-text-bot@v1.7.3