Fix build error

bom/pom.xml

@@ -40,6 +40,10 @@ THE SOFTWARE.
 
   <properties>
     <guavaVersion>30.1.1-jre</guavaVersion>
+    <!-- when updating the version of guava, check that forcing of errorprone is still needed.
+     Guava comes with error_prone_annotations version 2.5.1,
+     force it for the other plugins that use version 2.4.0 -->
+    <errorproneVersion>2.5.1</errorproneVersion>
     <slf4jVersion>1.7.30</slf4jVersion>
     <stapler.version>1532.vfcf95addcb5f</stapler.version>
     <groovy.version>2.4.12</groovy.version>
@@ -92,7 +96,12 @@ THE SOFTWARE.
       <dependency>
         <groupId>com.google.guava</groupId>
         <artifactId>guava</artifactId>
-        <version>11.0.1</version>
+        <version>${guavaVersion}</version>
+      </dependency>
+      <dependency>
+        <groupId>com.google.errorprone</groupId>
+        <artifactId>error_prone_annotations</artifactId>
+        <version>${errorproneVersion}</version>
       </dependency>
       <dependency>
         <groupId>com.google.inject</groupId>
@@ -150,7 +159,7 @@ THE SOFTWARE.
         <!-- the old artifactID for the servlet API -->
         <artifactId>servlet-api</artifactId>
         <version>[0]</version>
-        <!-- 
+        <!--
               "[0]" is a range that must be exactly 0
               this is different to "0" which is hint to use version 0.
               therefore unless anyone else uses ranges (they should not) this version will always win