v1.8.0-rc.1

What's Changed

• update base version to 1.8.x by @brharrington in #1526
• set baseline java version to 17 by @brharrington in #1527
• update to spring 6 by @brharrington in #1528
• fix misc warnings by @brharrington in #1529
• add specialized map for ref with double values by @brharrington in #1532
• eval: sum aggregation for gauges by @brharrington in #1533
• ci: enable snapshots for version branches by @brharrington in #1536
• update dependencies by @brharrington in #1539
• ci: add jdk20 by @brharrington in #1540
• lwc: model object for event by @brharrington in #1541
• lwc: add timestamp accessor by @brharrington in #1542
• lwc: add stack lang operators for events by @brharrington in #1543
• lwc: add client interface for processing events by @brharrington in #1545
• chart: ensure json objects are closed by @brharrington in #1546
• add small set of named colors by @brharrington in #1544
• add support for heatmaps by @brharrington in #1547
• add log-linear scale type by @brharrington in #1548

Full Changelog: v1.7.0...v1.8.0-rc.1