Bump Gradle version to 8.6 #464

Job	Run time
Attach pull request number	0s
Initial JDK 17 Build	12m 37s
CI Sanity Check	31s
Calculate Test Jobs	9s
Devtools Tests - JDK 17	14m 37s
Devtools Tests - JDK 21	13m 43s
JVM Tests - JDK 17	3h 57m 41s
Devtools Tests - JDK 17 Windows	20m 39s
JVM Tests - JDK 21	3h 53m 3s
Kubernetes Tests - JDK 17	13m 9s
Gradle Tests - JDK 17	28m 55s
JVM Tests - JDK 17 Windows	3h 51m 48s
Kubernetes Tests - JDK 21	12m 42s
Gradle Tests - JDK 17 Windows	51m 27s
Kubernetes Tests - JDK 17 Windows	16m 41s
Maven Tests - JDK 17	1h 3m 39s
Maven Tests - JDK 17 Windows	1h 24m 20s
Quickstarts Compilation - JDK 17	5m 34s
MicroProfile TCKs Tests	44m 51s
Native Tests - Virtual Thread - Main	22m 52s
Native Tests - Virtual Thread - Messaging	9m 52s
Native Tests - Main	8m 4s
Native Tests - Data1	31m 27s
Native Tests - Data2	26m 26s
Native Tests - Data3	24m 52s
Native Tests - Data4	18m 37s
Native Tests - Data5	19m 50s
Native Tests - Data6	24m 5s
Native Tests - Data7	37m 3s
Native Tests - Amazon	15m 43s
Native Tests - Messaging1	31m 3s
Native Tests - Messaging2	12m 59s
Native Tests - Security1	23m 0s
Native Tests - Security2	27m 46s
Native Tests - Security3	12m 18s
Native Tests - Cache	14m 1s
Native Tests - HTTP	39m 43s
Native Tests - Misc1	27m 27s
Native Tests - Misc2	16m 13s
Native Tests - Misc3	30m 59s
Native Tests - Misc4	45m 31s
Native Tests - Spring	20m 23s
Native Tests - gRPC	18m 20s
Native Tests - Windows - RESTEasy Jackson	5m 15s
Native Tests - DevTools Integration Tests	4m 17s
Native Tests - AWT, ImageIO and Java2D	7m 2s
Build report	55s
	1d 3h 42m 9s

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