Add explicit dependency on commons-collections, as it is used directly in Vitro code

dependencies/pom.xml

@@ -111,6 +111,11 @@
             <artifactId>commons-lang3</artifactId>
             <version>3.4</version>
         </dependency>
+        <dependency>
+            <groupId>commons-collections</groupId>
+            <artifactId>commons-collections</artifactId>
+            <version>3.2.1</version>
+        </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-csv</artifactId>