RFR: 7436: Update version to 8.1.1 in the jmc8 branch

[Marcus Hirt]

In preparation to the JMC 8.1.1 release.

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Commit messages:
 - 7436: Updating to 8.1.1

Changes: https://git.openjdk.java.net/jmc/pull/330/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=330&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7436
  Stats: 205 lines in 144 files changed: 0 ins; 0 del; 205 mod
  Patch: https://git.openjdk.java.net/jmc/pull/330.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/330/head:pull/330

PR: https://git.openjdk.java.net/jmc/pull/330