Fix internal pattern match for JIRA issues as per https://confluence.atlassian.com/display/JIRA/Changing+the+Project+Key+Format
Removed lowercase matching as it is not allowed in JIRA issues
Modified the test with no jira issues in order to test abc-123 is invalid
Modified the test with a jira issue in order to also test the issue ABC_D-123 is valid
Merge pull request #2 from agusmba/fix_internal_regexp

Fix internal pattern match for JIRA issues
added maven-amps-plugin plugin to pom.xml to fix problem described here: https://answers.atlassian.com/questions/277302/a-required-class-is-missing-lorg-apache-maven-plugin-buildpluginmanager
fixed test class name typo (YaccServcieImplTest -> YaccServiceImplTest)
updated jira issue id regex in README.md. created standalone unit test to test jira issue id extraction from commit message. (see pull request #2)