Add JMX metrics gatherer version 1.38.0-alpha (#34744)

Add JMX metrics gatherer version `1.38.0-alpha`.

cc @open-telemetry/java-contrib-approvers

Author: opentelemetrybot

receiver/jmxreceiver/supported_jars.go

@@ -31,6 +31,10 @@ func oldFormatProperties(c *Config, j supportedJar) error {
 // If you change this variable name, please open an issue in opentelemetry-java-contrib
 // so that repository's release automation can be updated
 var jmxMetricsGathererVersions = map[string]supportedJar{
+	"75d03922df2306086b9eee2daccbfd8c9b94ce140a482fb4698a839ec3d3f192": {
+		version: "1.38.0-alpha",
+		jar:     "JMX metrics gatherer",
+	},
 	"74d23e8714deab770c940a14175ab5dfd0cd0c16e198861e45a72fbb854bc727": {
 		version: "1.37.0-alpha",
 		jar:     "JMX metrics gatherer",