chore: do not require Java 17 for launching Gradle yet

We still require Java 17 for javac, however we could be fine if user
launches Gradle with Java 8 or Java 11.

So far no plugins seems to require Java 17, so let's ease the requiremenets

Signed-off-by: Vladimir Sitnikov <sitnikov.vladimir@gmail.com>

Author: vlsi

settings.gradle.kts

@@ -1,9 +1,5 @@
 rootProject.name = "sigstore-java-root"
 
-if (JavaVersion.current() < JavaVersion.VERSION_17) {
-    throw UnsupportedOperationException("Please use Java 17 or 21 for launching Gradle when building sigstore-java, the current Java is ${JavaVersion.current().majorVersion}")
-}
-
 includeBuild("build-logic-commons")
 includeBuild("build-logic")