Flutter 无法解析配置'；的所有项目：类路径'；。（颤振）

当我运行项目时，会出现以下错误：

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'android'.
> Could not resolve all artifacts for configuration ':classpath'.
   > Could not find google-services.jar (com.google.gms:google-services:4.3.0).
     Searched in the following locations:
         https://dl.google.com/dl/android/maven2/com/google/gms/google-services/4.3.0/google-services-4.3.0.jar
   > Could not find strict-version-matcher-plugin.jar (com.google.android.gms:strict-version-matcher-plugin:1.2.0).
     Searched in the following locations:
         https://dl.google.com/dl/android/maven2/com/google/android/gms/strict-version-matcher-plugin/1.2.0/strict-version-matcher-plugin-1.2.0.jar

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 1s
Finished with error: Gradle task assembleDebug failed with exit code 1

这是

build.gradle

：

buildscript {
    ext.kotlin_version = '1.3.50'
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.gms:google-services:4.3.0'
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

如何修复它？ 注意：此项目已成功运行，但当我再次从git下载它时，它会抛出此错误