Update logging configuration to log4j2/slf4j2

This ensures that log4j 1.x doesn't get pulled in by an older version of
the SLF4J implementation for log4j and updates the log4j.properties file
to the new format required by log4j2.

It also fixes a formatting issue where the use of Week Year "YYYY" vs
Year "yyyy" in the timestamp config resulted in a different year than
the current calendar year being printed in the logs.

Tested locally with lein run; logs appear as expected.

References:
https://docs.oracle.com/en/java/javase/12/docs/api/java.base/java/text/SimpleDateFormat.html

deps.edn

@@ -1,7 +1,7 @@
 {:deps
  {org.clojure/clojure {:mvn/version "1.10.0"}
   org.clojure/tools.cli {:mvn/version "0.4.1"}
-  org.slf4j/slf4j-log4j12 {:mvn/version "1.7.32"}
+  org.apache.logging.log4j/log4j-slf4j-impl {:mvn/version "2.17.0"}
   org.apache.logging.log4j/log4j-core
   {:mvn/version "2.17.0"
    :exclusions [javax.mail/mail

resources/log4j2.properties

@@ -0,0 +1,13 @@
+# log4j.rootLogger=INFO, console
+rootLogger.level = INFO
+
+# log to the console
+# log4j.appender.console=org.apache.log4j.ConsoleAppender
+appender.console.type = Console
+rootLogger.appenderRef.stdout.ref = STDOUT
+# log4j.appender.console.Target=System.out
+appender.console.name = STDOUT
+# log4j.appender.console.layout=org.apache.log4j.PatternLayout
+appender.console.layout.type = PatternLayout
+# log4j.appender.console.layout.ConversionPattern=%d{[MM/dd/YYYY HH:mm:ss]} \u001b[1m%c{2}\u001b[0m :: %m%n
+appender.console.layout.pattern = %d{[MM/dd/yyyy HH:mm:ss]} \u001b[1m%c{2}\u001b[0m :: %m%n