RFR: 7904053: Update version to 8.0 [v3]

[Christian Stein]

> Please review this trivial change updating the version to `8.0`; the upcoming release version of jtreg.

Christian Stein has updated the pull request incrementally with one additional commit since the last revision:

  Update make/build-support/version-numbers

-------------

Changes:
  - all: https://git.openjdk.org/jtreg/pull/271/files
  - new: https://git.openjdk.org/jtreg/pull/271/files/490c7fd0..ca917f89

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jtreg&pr=271&range=02
 - incr: https://webrevs.openjdk.org/?repo=jtreg&pr=271&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jtreg/pull/271.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/271/head:pull/271

PR: https://git.openjdk.org/jtreg/pull/271