Could not initialize class org.codehaus.groovy.vmplugin.v7.Java7

### Please fill in the following fields:
Unity editor version: 2019.4.0f1 and also multiple of 2019.3.x versions
External Dependency Manager version: 1.2.155
Source you installed EDM: Unity Package Manager
Features in External Dependency Manager in use: Android Resolver
Plugins SDK in use: Firebase, Facebook, IronSource
Platform you are using the Unity editor on: Mac OS Catalina (10.15.5)
Platform you are targeting: Android
Scripting Runtime: IL2CPP

### Please describe the issue here:
I am unable to run Android Resolver because of exception:

```
Failed to run '/Users/peter/Projects/hopply/Temp/PlayServicesResolverGradle/gradlew --no-daemon -b "/Users/peter/Projects/hopply/Temp/PlayServicesResolverGradle/PlayServicesResolver.scripts.download_artifacts.gradle" "-PANDROID_HOME=/Applications/Unity/Hub/Editor/2019.4.0f1/PlaybackEngines/AndroidPlayer/SDK" "-PTARGET_DIR=/Users/peter/Projects/hopply/Assets/Plugins/Android" "-PMAVEN_REPOS=https://dl.bintray.com/ironsource-mobile/android-sdk/;https://maven.google.com/;https://dl.bintray.com/ironsource-mobile/android-adapters/;file:////Users/peter/Projects/hopply/Library/PackageCache/com.google.firebase.app@6.15.0/Firebase/m2repository;file:////Users/peter/Projects/hopply/Library/PackageCache/com.google.firebase.remote-config@6.15.0/Firebase/m2repository;file:////Users/peter/Projects/hopply/Library/PackageCache/com.google.firebase.analytics@6.15.0/Firebase/m2repository" "-PPACKAGES_TO_COPY=com.android.support:support-v4:25.3.1;com.android.support:appcompat-v7:25.3.1;com.android.support:cardview-v7:25.3.1;com.android.support:customtabs:25.3.1;com.parse.bolts:bolts-android:1.4.0;com.facebook.android:facebook-core:[6.2.0, 7);com.facebook.android:facebook-applinks:[6.2.0, 7);com.facebook.android:facebook-login:[6.2.0, 7);com.facebook.android:facebook-share:[6.2.0, 7);com.facebook.android:facebook-gamingservices:[6.2.0, 7);com.ironsource.sdk:mediationsdk:6.16.1;com.google.android.gms:play-services-ads-identifier:17.0.0;com.google.android.gms:play-services-ads:19.1.0;com.ironsource.adapters:admobadapter:4.3.9;com.ironsource.adapters:unityadsadapter:4.3.3;com.google.firebase:firebase-common:19.3.0;com.google.firebase:firebase-analytics:17.4.1;com.google.firebase:firebase-app-unity:6.15.0;com.google.firebase:firebase-config:19.1.4;com.google.firebase:firebase-config-unity:6.15.0;com.google.firebase:firebase-analytics-unity:6.15.0" "-PUSE_JETIFIER=1" "-PDATA_BINDING_VERSION=3.4.0"'

java.lang.NoClassDefFoundError: Could not initialize class org.codehaus.groovy.vmplugin.v7.Java7
at org.codehaus.groovy.vmplugin.VMPluginFactory.(VMPluginFactory.java:43)
at org.codehaus.groovy.reflection.GroovyClassValueFactory.(GroovyClassValueFactory.java:35)
at org.codehaus.groovy.reflection.ClassInfo.(ClassInfo.java:109)
at org.codehaus.groovy.reflection.ReflectionCache.getCachedClass(ReflectionCache.java:95)
at org.codehaus.groovy.reflection.ReflectionCache.(ReflectionCache.java:39)
at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.registerMethods(MetaClassRegistryImpl.java:209)
at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.(MetaClassRegistryImpl.java:107)
at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.(MetaClassRegistryImpl.java:85)
at groovy.lang.GroovySystem.(GroovySystem.java:36)
at org.codehaus.groovy.runtime.InvokerHelper.(InvokerHelper.java:86)
at groovy.lang.GroovyObjectSupport.getDefaultMetaClass(GroovyObjectSupport.java:59)
at groovy.lang.GroovyObjectSupport.(GroovyObjectSupport.java:32)
at org.gradle.api.internal.plugins.DefaultExtraPropertiesExtension.(DefaultExtraPropertiesExtension.java:29)
at org.gradle.api.internal.plugins.DefaultConvention.(DefaultConvention.java:47)
at org.gradle.api.internal.ExtensibleDynamicObject.(ExtensibleDynamicObject.java:58)
at org.gradle.initialization.DefaultSettings.(DefaultSettings.java:93)
at org.gradle.initialization.DefaultSettings_Decorated.(Unknown Source)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
...
```

I found out that it is related to Gradle issue: https://github.com/gradle/gradle/issues/10248
So I tried to:
- manually change version of Gradle in Temp/PlayServicesResolverGradle/gradle/wrapper/gradle-wrapper.properties from gradle-5.1.1-bin.zip to gradle-6.4-bin.zip
- run that long gradlew command by myself (...gradlew --no-daemon -b "/Users/peter/Projects/...)
And it finishes without any problem.

My suggestion is to upgrade the Gradle used by resolver.

### Please answer the following, if applicable:
What's the issue repro rate?
**99%**

In the past, I was able to run Android resolver successfully 3 times exactly. I really don't know why it worked, because it was always with the same configuration after countless of failures.