Emphasize checklist step to try Maven jars build before release

to not break Android build
ref: Gitlab MR !64

installer/resources/checklist.md

@@ -31,10 +31,13 @@
 - Trial Debian build: Run 'ant debcheckpatch' and fix any issues.
   Build and test a preliminary Debian build with 'ant debian' and fix any issues
 
-- Javadoc test: 'ant javadoc' and 'ant mavenCentral.deps'
+- Javadoc test: 'ant javadoc'
   with a recent Oracle JDK (12+), and fix any issues.
   Oracle JDK will error on things that OpenJDK does not!
 
+- Java 7 test: 'ant mavenCentral.deps' to ensure
+  that Android will build correcly; fix any issues
+
 
 ## A day or two before