Concurrent spotlessJava tasks with eclipse hanging on empty p2 repository

With spotless gradle plugin 7.0.4 we are seeing the spotlessJava tasks keeps hanging in our CI environments. further investigation showed this seems like a concurrency issue. jstack gives me this stacktrace with two entries (for each active spotless java task) similar to this:

```
"Execution worker Thread 6" #117 [1841467] prio=5 os_prio=0 cpu=2438.51ms elapsed=100.17s tid=0x00007fcc0400e4e0 nid=1841467 in Object.wait() [0x00007fcc415e5000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait0(java.base@21.0.6/Native Method)
- waiting on
at java.lang.Object.wait(java.base@21.0.6/Object.java:366)
at java.lang.Object.wait(java.base@21.0.6/Object.java:339)
at dev.equo.solstice.p2.LockFile.(LockFile.java:40)
- locked <0x00000000d2a38d00> (a java.lang.Object)
at dev.equo.solstice.p2.P2Client.(P2Client.java:72)
at dev.equo.solstice.p2.P2Model.queryRaw(P2Model.java:105)
at dev.equo.solstice.p2.P2Model.query(P2Model.java:136)
at com.diffplug.spotless.extra.EquoBasedStepBuilder.lambda$build$0(EquoBasedStepBuilder.java:128)
at com.diffplug.spotless.extra.EquoBasedStepBuilder$$Lambda/0x00007fcd9932a9d0.get(Unknown Source)
at com.diffplug.spotless.JarState$Promised.get(JarState.java:73)
at com.diffplug.spotless.extra.EquoBasedStepBuilder$EquoStep.state(EquoBasedStepBuilder.java:193)
at com.diffplug.spotless.extra.EquoBasedStepBuilder.lambda$build$cc29b8bc$1(EquoBasedStepBuilder.java:144)
at com.diffplug.spotless.extra.EquoBasedStepBuilder$$Lambda/0x00007fcd9932c700.apply(Unknown Source)
at com.diffplug.spotless.FormatterStepSerializationRoundtrip.stateSupplier(FormatterStepSerializationRoundtrip.java:57)
at com.diffplug.spotless.FormatterStepSerializationRoundtrip$HackClone$$Lambda/0x00007fcd9972f3a8.get(Unknown Source)
at com.diffplug.spotless.ThrowingEx.get(ThrowingEx.java:67)
at com.diffplug.spotless.FormatterStepSerializationRoundtrip$HackClone.writeObject(FormatterStepSerializationRoundtrip.java:113)
at java.lang.invoke.LambdaForm$DMH/0x00007fcd9813c000.invokeSpecial(java.base@21.0.6/LambdaForm$DMH)
at java.lang.invoke.LambdaForm$MH/0x00007fcd98018c00.invoke(java.base@21.0.6/LambdaForm$MH)
at java.lang.invoke.Invokers$Holder.invokeExact_MT(java.base@21.0.6/Invokers$Holder)
at jdk.internal.reflect.DirectMethodHandleAccessor.invokeImpl(java.base@21.0.6/DirectMethodHandleAccessor.java:154)
at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(java.base@21.0.6/DirectMethodHandleAccessor.java:103)
at java.lang.reflect.Method.invoke(java.base@21.0.6/Method.java:580)
at java.io.ObjectStreamClass.invokeWriteObject(java.base@21.0.6/ObjectStreamClass.java:1072)
at java.io.ObjectOutputStream.writeSerialData(java.base@21.0.6/ObjectOutputStream.java:1529)
at java.io.ObjectOutputStream.writeOrdinaryObject(java.base@21.0.6/ObjectOutputStream.java:1451)
at java.io.ObjectOutputStream.writeObject0(java.base@21.0.6/ObjectOutputStream.java:1194)
at java.io.ObjectOutputStream.writeObject(java.base@21.0.6/ObjectOutputStream.java:358)
at com.diffplug.spotless.ConfigurationCacheHackList.writeObject(ConfigurationCacheHackList.java:76)
at java.lang.invoke.LambdaForm$DMH/0x00007fcd9813c000.invokeSpecial(java.base@21.0.6/LambdaForm$DMH)

```

this is reproducible when I cleanup the `~/.m2/repository/dev/equo/p2-data/` folder locally and run our build again.
In general we got biten by this dynamic p2 lookups and I would love to see the resolution of those artifacts would be wired into the gradle dependency resolution instead of being completely hidden deep down in the spotless logic. This currently blocks us from updating to newer spotless gradle plugin versions.

Reproduziere den Hänger, indem du ~/.m2/repository/dev/equo/p2-data/ leerst und nebenläufige spotlessJava-Tasks ausführst. Beginne mit den LockFile- und P2Client-Einträgen im bereitgestellten Stack Trace und verfolge dann die Aufrufe von EquoBasedStepBuilder und P2Model; abgeschlossen ist die Aufgabe, wenn die nebenläufigen Tasks abgeschlossen werden, sobald das p2-Repository leer ist.

Vom Indexierungsmodell aus dem Issue-Text verfasst.