GitHub actions (#2)

* Updated readme, enabled automatc testing

* Snapshot support

* Release CI support

Co-authored-by: Salomon BRYS <salomon@kodein.net>

jni/build.gradle.kts

@@ -49,12 +49,15 @@ sealed class Cross {
 val buildNativeJni by tasks.creating {
     group = "build"
 }
+val noCrossCompile: String? by project
 fun creatingBuildNativeJni(target: String, cross: Cross?) = tasks.creating(Exec::class) {
     group = "build"
     dependsOn(generateJniHeaders)
     dependsOn(":native:buildSecp256k1${target.capitalize()}")
     buildNativeJni.dependsOn(this)
 
+    if (noCrossCompile == "true") onlyIf { cross == null }
+
     inputs.files(projectDir.resolve("build.sh"))
     outputs.dir(buildDir.resolve("build/cmake/$target"))