<dependency>
			<groupId>com.alibaba.cloud</groupId>
			<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-openfeign</artifactId>
			<version>2.1.1.RELEASE</version>
		</dependency>
		<dependency>
		    <groupId>com.netflix.archaius</groupId>
		    <artifactId>archaius-core</artifactId>
		    <version>0.7.6</version>
		    <exclusions>
		        <exclusion>
		            <groupId>com.google.guava</groupId>
		            <artifactId>guava</artifactId>
		        </exclusion>
		    </exclusions>
		</dependency>

添加openfeign依赖的时候，不指定版本号会报错，说没有指定版本missing，添加的springcloud和springcloud alibaba版本如下：

	<dependencyManagement>
		<dependencies>
			<!--整合spring cloud-->
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Greenwich.SR1</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
			<!--整合spring cloud alibaba-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.1.2.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
		</dependencies>
	</dependencyManagement>

spring boot的版本是 2.1.9.RELEASE，

请教下老师，为什么添加openfeign要指定版本呢？