RFR: 8035: Update Java version in GHA workflow to 11.0.18 [v2]

[Christoph Langer]

> We can bump the GHA JDK to 11.0.18.

Christoph Langer has updated the pull request incrementally with one additional commit since the last revision:

  Add copyright header

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

Changes:
  - all: https://git.openjdk.org/jmc/pull/465/files
  - new: https://git.openjdk.org/jmc/pull/465/files/be7c5dbe..ed5388c7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=465&range=01
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=465&range=00-01

  Stats: 34 lines in 1 file changed: 34 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jmc/pull/465.diff
  Fetch: git fetch https://git.openjdk.org/jmc pull/465/head:pull/465

PR: https://git.openjdk.org/jmc/pull/465