Prepare release 1.13.0 (#304)

OpenTelemetry Java Bot · web-flow · commit d953fb1b8f97 · 2022-04-19T22:40:30.000-07:00
diff --git a/version.gradle.kts b/version.gradle.kts
@@ -1,4 +1,4 @@
-val snapshot = true
+val snapshot = false
 
 allprojects {
   var ver = "1.13.0"
