update license name to match SPDX license list and also Wildfly

Currently the license name in the pom.xml is "Apache License Version 2.0", I think we should change it to "Apache License 2.0" because:
1) It is the name that is mentioned in the SPDX license database [1]
2) It avoids issues in Wildfly when creating the licenses.xml file as both Wildfly-Core and Wildfly expects a license calling "Apache License 2.0" to match the license file in [2][3].

[1] https://spdx.org/licenses/
[2] https://github.com/wildfly/wildfly-core/tree/master/core-feature-pack/common/src/main/resources/content/docs/licenses
[3] https://github.com/wildfly/wildfly/tree/master/ee-feature-pack/common/src/main/resources/content/docs/licenses/