Update gradle version to be compatible with new react native versions

[rednebmas]

Closes #20.

I have not tested the demo application in this repo.

For google, the error was:

* Exception is:
org.gradle.api.GradleScriptException: A problem occurred evaluating project ':react-native-touch-through-view'.
	at org.gradle.groovy.scripts.internal.DefaultScriptRunnerFactory$ScriptRunnerImpl.run(DefaultScriptRunnerFactory.java:93)
	at org.gradle.configuration.DefaultScriptPluginFactory$ScriptPluginImpl.lambda$apply$0(DefaultScriptPluginFactory.java:133)
	at org.gradle.configuration.ProjectScriptTarget.addConfiguration(ProjectScriptTarget.java:79)
	at org.gradle.configuration.DefaultScriptPluginFactory$ScriptPluginImpl.apply(DefaultScriptPluginFactory.java:136)
	at org.gradle.configuration.BuildOperationScriptPlugin$1.run(BuildOperationScriptPlugin.java:65)
	at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
Caused by: org.gradle.internal.metaobject.AbstractDynamicObject$CustomMessageMissingMethodException: Could not find method compile() for arguments [com.facebook.react:react-native:+] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.
	at org.gradle.internal.metaobject.AbstractDynamicObject$CustomMissingMethodExecutionFailed.<init>(AbstractDynamicObject.java:190)
	at org.gradle.internal.metaobject.AbstractDynamicObject.methodMissingException(AbstractDynamicObject.java:184)
	at org.gradle.internal.metaobject.ConfigureDelegate.invokeMethod(ConfigureDelegate.java:86)
	at build_bixbjew3xjliyeao0cem78ao0$_run_closure3.doCall(/Users/sam/code/react-native/TheraCentricRN/node_modules/react-native-touch-through-view/android/build.gradle:51)
	at org.gradle.groovy.scripts.BasicScript.invokeMethod(BasicScript.java:84)
	at build_bixbjew3xjliyeao0cem78ao0.run(/Users/sam/code/react-native/TheraCentricRN/node_modules/react-native-touch-through-view/android/build.gradle:50)

[rednebmas]

Didn't work when this was 7.3.3 like the URL in gradle-wrapper.properties. I am not sure why, I am not an Android dev. Happy to update either if someone knows the right thing to do.