RFR: 1102: Document minimum required JDK version 16 for Skara [v2]

[Erik Joelsson]

> Change documentation to reflect that Skara now requires JDK 16 to build.

Erik Joelsson has updated the pull request incrementally with one additional commit since the last revision:

  Update example

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Changes:
  - all: https://git.openjdk.java.net/skara/pull/1195/files
  - new: https://git.openjdk.java.net/skara/pull/1195/files/2720256b..35fa6b8c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1195&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1195&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/1195.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1195/head:pull/1195

PR: https://git.openjdk.java.net/skara/pull/1195