POM: update clojure version to 1.12.0

Addresses CVE-2017-20189.

Author: ctrueden

pom.xml

@@ -97,7 +97,7 @@
 		<license.copyrightOwners>Board of Regents of the University of
 Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
 Institute of Molecular Cell Biology and Genetics.</license.copyrightOwners>
-		<clojure.version>1.8.0</clojure.version>
+		<clojure.version>1.12.0</clojure.version>
 
 		<!-- NB: Deploy releases to the SciJava Maven repository. -->
 		<releaseProfiles>sign,deploy-to-scijava</releaseProfiles>