STATISTICS-23: Order of arguments in "GammaDistribution" sampler.

Cf. RNG-96.
diff --git a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/GammaDistribution.java b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/GammaDistribution.java
index f4e8dd0..225b19b 100644
--- a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/GammaDistribution.java
+++ b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/GammaDistribution.java
@@ -343,6 +343,6 @@
     @Override
     public ContinuousDistribution.Sampler createSampler(final UniformRandomProvider rng) {
         // Gamma distribution sampler.
-        return new AhrensDieterMarsagliaTsangGammaSampler(rng, scale, shape)::sample;
+        return new AhrensDieterMarsagliaTsangGammaSampler(rng, shape, scale)::sample;
     }
 }