build: upgrade maven-install-plugin to 3.1.2 for offline mirror compatibility (GoogleCloudPlatform#400)

Change-Id: I3465574727c1f70aa500941fb08a85ca708963bb

Co-authored-by: Anshul Patni <anshulpatni@google.com>

Author: AnshulPatni

function-maven-plugin/pom.xml

@@ -107,6 +107,11 @@
           <artifactId>maven-enforcer-plugin</artifactId>
           <version>3.5.0</version>
         </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>3.1.2</version>
+        </plugin>
       </plugins>
     </pluginManagement>
     <plugins>

functions-framework-api/pom.xml

@@ -125,6 +125,11 @@
           <artifactId>maven-enforcer-plugin</artifactId>
           <version>3.5.0</version>
         </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>3.1.2</version>
+        </plugin>
         <plugin>
           <artifactId>maven-javadoc-plugin</artifactId>
           <version>${maven-javadoc-plugin.version}</version>

invoker/pom.xml

@@ -90,6 +90,11 @@
           <artifactId>maven-enforcer-plugin</artifactId>
           <version>3.5.0</version>
         </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>3.1.2</version>
+        </plugin>
       </plugins>
     </pluginManagement>
   </build>