Fail to merge manifest with admob [SOLVED]

So im using de admob plugin(only using this one, nothing else) to add ads but when im trying to build the apk i get 3 errors:

   Error: Error while saving blame file, build will continue
     Error: El prefijo "tools" para el atributo "tools:overrideLibrary" asociado a un tipo de elemento "uses-sdk" no está enlazado.
 
 UnityEditor.HostView:OnGUI()

 AndroidSDKToolsException: Unable to merge android manifests. See the Console for more details. 
 UnityEditor.Android.AndroidSDKTools.DetectErrorsAndWarnings (System.String logMessages, System.String errorMsg)
 UnityEditor.Android.AndroidSDKTools.RunCommandInternal (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
 UnityEditor.Android.AndroidSDKTools.RunCommandSafe (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
 UnityEditor.Android.AndroidSDKTools.RunCommand (System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
 UnityEditor.Android.AndroidSDKTools.RunCommand (System.String[] sdkToolCommand, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
 UnityEditor.Android.AndroidSDKTools.RunCommand (System.String[] sdkToolCommand, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
 UnityEditor.Android.AndroidSDKTools.MergeManifests (System.String target, System.String mainManifest, System.String[] libraryManifests, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit)
 UnityEditor.Android.PostProcessor.Tasks.GenerateManifest.MergeManifests (UnityEditor.Android.PostProcessor.PostProcessorContext context, System.String targetManifest, System.String mainManifest)
 UnityEditor.Android.PostProcessor.Tasks.GenerateManifest.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
 UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
 UnityEditor.HostView:OnGUI()

And

 UnityEditor.BuildPlayerWindow+BuildMethodException: Build failed with errors.
   at UnityEditor.BuildPlayerWindow+DefaultBuildMethods.BuildPlayer (BuildPlayerOptions options) [0x001b9] in C:\buildslave\unity\build\Editor\Mono\BuildPlayerWindowBuildMethods.cs:162 
   at UnityEditor.BuildPlayerWindow.CallBuildMethods (Boolean askForBuildLocation, BuildOptions defaultBuildOptions) [0x00050] in C:\buildslave\unity\build\Editor\Mono\BuildPlayerWindowBuildMethods.cs:83 
 UnityEditor.HostView:OnGUI()
 

https://github.com/unity-plugins/Firebase-Admob-Unity/wiki#install this is the plugin im using

So what i had to do (i dont know if is the best solution but it worked) i removed the manifest from plugin\android\androidmanifest, then i edited the one in unity\editor\data\playbackengine\androidplayer\apk so that it matches both and now it builds