Fix build. (#2190)

Author: vkryachko

.gitignore

@@ -8,3 +8,4 @@ google-services.json
 _artifacts
 .DS_Store
 firebase-crashlytics-ndk/.externalNativeBuild/
+firebase-crashlytics-ndk/.cxx/

build.gradle

@@ -29,7 +29,6 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.0.0'
         classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.12'
         classpath 'net.ltgt.gradle:gradle-errorprone-plugin:1.3.0'
         classpath 'org.jsoup:jsoup:1.13.1'

buildSrc/src/main/java/com/google/firebase/gradle/plugins/FirebaseLibraryExtension.java

@@ -121,11 +121,11 @@ public void releaseWith(Project releaseWithProject) {
       this.project.setVersion(releaseWithProject.getVersion());
 
       String latestRelease = "latestReleasedVersion";
-      if (releaseWithProject.getExtensions().getExtraProperties().has(latestRelease)) {
+      if (releaseWithProject.hasProperty(latestRelease)) {
         this.project
             .getExtensions()
             .getExtraProperties()
-            .set(latestRelease, releaseWithProject.getProperties().get(latestRelease));
+            .set(latestRelease, releaseWithProject.property(latestRelease));
       }
 
     } catch (UnknownDomainObjectException ex) {
@@ -169,8 +169,7 @@ public String getVersion() {
 
   public Optional<String> getLatestReleasedVersion() {
     if (project.hasProperty("latestReleasedVersion")) {
-      return Optional.of(
-          project.getExtensions().getExtraProperties().get("latestReleasedVersion").toString());
+      return Optional.of(project.property("latestReleasedVersion").toString());
     }
     return Optional.empty();
   }