GH-977 - Drop integration builds against Boot 3.0.

The examples use a feature not available in Boot 3.0 and fail because of that, not because of general incompatibility.

Author: odrotbohm

.github/workflows/integration.yaml

@@ -11,7 +11,6 @@ jobs:
       fail-fast: false
       matrix:
         version:
-        - '3.0.13'
         - '3.1.12'
         - '3.3.6'
         - '3.3.7-SNAPSHOT'