Revise cross-compile config (#21)

pom.xml

@@ -26,14 +26,13 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <maven.compiler.source>1.7</maven.compiler.source>
-    <maven.compiler.target>1.7</maven.compiler.target>
+    <maven.compiler.release>7</maven.compiler.release>
     <testng.version>6.10</testng.version>
-    <toolchains-plugin.version>3.0.0</toolchains-plugin.version>
-    <surefire-plugin.version>2.22.2</surefire-plugin.version>
+    <compiler-plugin.version>3.8.1</compiler-plugin.version>
+    <surefire-plugin.version>3.0.0-M5</surefire-plugin.version>
     <source-plugin.version>3.2.0</source-plugin.version>
     <javadoc-plugin.version>3.1.1</javadoc-plugin.version>
-    <guava.version>28.1-android</guava.version>
+    <guava.version>30.1.1-android</guava.version>
     <gpg-plugin.version>1.6</gpg-plugin.version>
     <staging-plugin.version>1.6.8</staging-plugin.version>
     <release-plugin.version>2.5.3</release-plugin.version>
@@ -101,18 +100,18 @@
       <plugins>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-toolchains-plugin</artifactId>
-          <version>${toolchains-plugin.version}</version>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <version>${compiler-plugin.version}</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-source-plugin</artifactId>
-          <version>${source-plugin.version}</version>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>${surefire-plugin.version}</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-surefire-plugin</artifactId>
-          <version>${surefire-plugin.version}</version>
+          <artifactId>maven-source-plugin</artifactId>
+          <version>${source-plugin.version}</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -134,51 +133,16 @@
           <artifactId>maven-release-plugin</artifactId>
           <version>${release-plugin.version}</version>
         </plugin>
-        <plugin>
-          <groupId>org.eclipse.m2e</groupId>
-          <artifactId>lifecycle-mapping</artifactId>
-          <version>1.0.0</version>
-          <configuration>
-            <lifecycleMappingMetadata>
-              <pluginExecutions>
-                <pluginExecution>
-                  <pluginExecutionFilter>
-                    <groupId>org.apache.maven.plugins</groupId>
-                    <artifactId>maven-toolchains-plugin</artifactId>
-                    <versionRange>[1.0.0,)</versionRange>
-                    <goals>
-                      <goal>toolchain</goal>
-                    </goals>
-                  </pluginExecutionFilter>
-                  <action>
-                    <execute />
-                  </action>
-                </pluginExecution>
-              </pluginExecutions>
-            </lifecycleMappingMetadata>
-          </configuration>
-        </plugin>
       </plugins>
     </pluginManagement>
     <plugins>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-toolchains-plugin</artifactId>
-        <executions>
-          <execution>
-            <goals>
-              <goal>toolchain</goal>
-            </goals>
-          </execution>
-        </executions>
-        <configuration>
-          <toolchains>
-            <jdk>
-              <version>1.7</version>
-              <vendor>oracle</vendor>
-            </jdk>
-          </toolchains>
-        </configuration>
+        <artifactId>maven-compiler-plugin</artifactId>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
@@ -192,10 +156,6 @@
           </execution>
         </executions>
       </plugin>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-surefire-plugin</artifactId>
-      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>