RFR: 1004: Skara bots fail to parse openjfx11.0.12 version

[Erik Joelsson]

This patch adds the ability to parse prefixes for JEP322 versions in JBS. One typical such prefix is openjfx, but I chose to not enumerate valid ones here but instead accept any prefix matching [a-z]+.

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Commit messages:
 - Handle openjfxX.Y.Z versions

Changes: https://git.openjdk.java.net/skara/pull/1142/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1142&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1004
  Stats: 19 lines in 2 files changed: 19 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/1142.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1142/head:pull/1142

PR: https://git.openjdk.java.net/skara/pull/1142