[jdk11u] RFR: 8314678: Bump update version for OpenJDK: jdk-11.0.20.1

[Ben Taylor]

Proposed branch for [JDK-8314678](https://bugs.openjdk.org/browse/JDK-8314678)


Note that the merge preview on this branch will be incorrect as there is no upstream jdk11.0.20 branch, only a 11.0.20-ga tag. As such the PR is based on `master`.
Changes against the GA tag can be viewed at [diff](https://github.com/openjdk/jdk11u/compare/jdk-11.0.20-ga...benty-amzn:jdk11u:jdk11.0.20.1?expand=1)

See also previous discussion on [jdk17u #374](https://github.com/openjdk/jdk17u/pull/374) and [jdk17u #375](https://github.com/openjdk/jdk17u/pull/375)

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Commit messages:
 - 8313765: Invalid CEN header (invalid zip64 extra data field size)
 - 8314678: Bump update version for OpenJDK: jdk-11.0.20.1

Changes: https://git.openjdk.org/jdk11u/pull/76/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u&pr=76&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314678
  Stats: 1004 lines in 6 files changed: 987 ins; 1 del; 16 mod
  Patch: https://git.openjdk.org/jdk11u/pull/76.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u.git pull/76/head:pull/76

PR: https://git.openjdk.org/jdk11u/pull/76