To get all architectures just add ndkArchitecture configuration onto your pom.xml:
<plugin>
<groupId>com.jayway.maven.plugins.android.generation2</groupId>
<artifactId>android-maven-plugin</artifactId>
<version>3.8.2</version>
<configuration>
<sdk>
<platform>${sdk.platform}</platform>
</sdk>
<ndkArchitecture>armeabi armeabi-v7a x86</ndkArchitecture>
</configuration>
</plugin>
But in order to work maven android plugin version must be: 3.8.2 (with maven 3.1.1)