Update maven installation instructions to include 3.1.1 installation
Update maven installation instructions to include 3.1.1 installation

jdonmoyer/deckard-gradle,403462630/deckard-gradle-test,DroidsOnRoids/deckard-gradle,WonderCsabo/deckard-maven,ankitrokdeonsns/sulabh-android-app,vogellacompany/deckard-gradle,toshihirock/AndroidEspresso2Sample,WonderCsabo/deckard-gradle,eggertj12/Oturgjold,seadowg/deckard-gradle,yjliugit/gradletest,robolectric/deckard-maven,seadowg/windsock-android,robolectric/deckard,seadowg/windsock-android,Mounika-Chirukuri/deckard,sweetleon/android-sample-todo-list,robolectric/deckard-maven,0359xiaodong/deckard,seadowg/windsock-android