[AMQ-7295] Update JTA spec to fix parent pom corruption

JTA spec dependency has corrupt parent pom reference leading to:

Resolved pom file .m2/repository/org/apache/geronimo/specs/specs/1.1/specs-1.1.pom: Failed to parse artifact POM model: expected START_TAG or END_TAG not TEXT (position: TEXT seen ...</developers>\n `\n <p... @91:7)

Fix from: https://issues.apache.org/jira/browse/AMQ-7295