Update kotlinx.metadata to 0.5.0 (#245)

diff --git a/gradle.properties b/gradle.properties
index 3ee91aa..693ffa4 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -9,7 +9,7 @@
 asm_version=9.3
 slf4j_version=1.8.0-alpha2
 junit_version=4.12
-kotlinx_metadata_version=0.4.2
+kotlinx_metadata_version=0.5.0
 
 maven_version=3.5.3