build: bump JDK to 21.0.6

[jjohannes]

This is the latest JDK 21 release.

[github-actions]

JUnit Test Report

   68 files  ±0     68 suites  ±0   2m 22s ⏱️ +2s
1 273 tests ±0  1 270 ✅ ±0   3 💤 ±0  0 ❌ ±0 
7 128 runs  ±0  7 109 ✅ ±0  19 💤 ±0  0 ❌ ±0 

Results for commit 0351d21. ± Comparison against base commit 561c634.

This pull request removes 8 and adds 7 tests. Note that renamed tests count towards both.

, 1
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [1] FLOAT, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833aa68@1a8b22b5, [0.1, 0.5, 100.0], 12, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833ac78@5f781173
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [1] STRING, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf183479f8@7a47f0be, [string 1, testing here, testing there], com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf18347c08@2d8087da
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [2] BYTES, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1834c000@7e1fb22c, [010203, ff7f0f, 42da07370bff], com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1834c210@38fc34fd
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [2] DOUBLE, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833ae88@649009d6, [0.1, 0.5, 100.0, 1.7653472635472653E240], 32, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833b098@652f26da
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [3] BOOL, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833b2a8@484a5ddd, [true, false, false, true, true, true], 6, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833b4b8@6796a873
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [4] ENUM, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833b6c8@3acc3ee, [Mock for EnumWithProtoMetadata, hashCode: 748807322, Mock for EnumWithProtoMetadata, hashCode: 686366573, Mock for EnumWithProtoMetadata, hashCode: 382992974], 3, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007faf1833b8d8@dbda472
com.hedera.pbj.runtime.Utf8ToolsTest ‑ [4] 

com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [1] FLOAT, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833aa68@1a8b22b5, [0.1, 0.5, 100.0], 12, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833ac78@5f781173
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [1] STRING, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f78783479f8@7a47f0be, [string 1, testing here, testing there], com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f7878347c08@2d8087da
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [2] BYTES, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787834c000@7e1fb22c, [010203, ff7f0f, 42da07370bff], com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787834c210@38fc34fd
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [2] DOUBLE, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833ae88@649009d6, [0.1, 0.5, 100.0, 1.7653472635472653E240], 32, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833b098@652f26da
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [3] BOOL, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833b2a8@484a5ddd, [true, false, false, true, true, true], 6, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833b4b8@6796a873
com.hedera.pbj.runtime.ProtoWriterToolsTest ‑ [4] ENUM, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833b6c8@3acc3ee, [Mock for EnumWithProtoMetadata, hashCode: 748807322, Mock for EnumWithProtoMetadata, hashCode: 686366573, Mock for EnumWithProtoMetadata, hashCode: 382992974], 3, com.hedera.pbj.runtime.ProtoWriterToolsTest$$Lambda/0x00007f787833b8d8@dbda472
com.hedera.pbj.runtime.Utf8ToolsTest ‑ [4] 
, 1

[github-actions]

Integration Test Report

    393 files  ±0      393 suites  ±0   11m 17s ⏱️ - 4m 26s
114 769 tests ±0  114 769 ✅ ±0  0 💤 ±0  0 ❌ ±0 
114 997 runs  ±0  114 997 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 0351d21. ± Comparison against base commit 561c634.

This pull request removes 3 and adds 3 tests. Note that renamed tests count towards both.

com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [1] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007f35a0606dc0@456733c9
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [2] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007f35a0606ff0@6497fcd4
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [3] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007f35a0607220@1415c942

com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [1] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007fd718605590@4aa438e1
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [2] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007fd7186057c0@5bb43336
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [3] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007fd7186059f0@55979ff3