修复Spring的配置的xsd文件需要对packageExpression的值做校验

skywalking-sdk-plugin/spring-plugin/src/main/resources/META-INF/skywalking.xsd

 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <xsd:schema xmlns="http://cloud.asiainfo.com/schema/skywalking"
-	xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://cloud.asiainfo.com/schema/skywalking">
+            xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://cloud.asiainfo.com/schema/skywalking">
 
-	<xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace"/>
 
-	<xsd:element name="trace" type="traceType">
-	</xsd:element>
+    <xsd:element name="trace" type="traceType">
+    </xsd:element>
 
-	<xsd:complexType name="traceType">
-		<xsd:attribute name="packageExpression" type="xsd:string" use="required" />
-		<xsd:attribute name="classExpression" type="xsd:string" use="optional" default="*" />
-	</xsd:complexType>
+    <xsd:complexType name="traceType">
+        <xsd:attribute name="packageExpression" use="required">
+            <xsd:simpleType>
+                <xsd:restriction base="xsd:string">
+                    <xsd:pattern value="[\w|.]*\.\*"/>
+                </xsd:restriction>
+            </xsd:simpleType>
+        </xsd:attribute>
+        <xsd:attribute name="classExpression" type="xsd:string" use="optional" default="*"/>
+    </xsd:complexType>
 </xsd:schema>
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