maven-pmd-plugin update to 3.7

[venusdrogon]

maven-pmd-plugin update to 3.7

    Release Notes - Maven PMD Plugin - Version 3.7

Bug

• [MPMD-162] - PMD/CPD report does not take into account pmd.excludeFromFailureFile
• [MPMD-178] - ExcludeRoots doesn't handle subdirectories (PMD isn't working nicely with Android projects)
• [MPMD-213] - Remove unnecessary (read-only) parameter "language" from check goal
• [MPMD-219] - Maven PMD Plugin ignores PMD processing errors

Improvement

• [MPMD-212] - Add documentation and IT for MPMD-206
• [MPMD-220] - Upgrade to PMD 5.5.1 (requires Java 7)
• [MPMD-227] - Document multimodule configuration example
• [MPMD-228] - Upgrade maven-plugins to version 30
• [MPMD-229] - Cleanup POM, remove temporary workarounds

Task

• [MPMD-196] - Do not rely in tests on toLowerCase but on toLowerCase(Locale.ROOT)
• [MPMD-226] - Require Java 7