feat: upgrade org.slf4j:slf4j-log4j12 from 1.7.25 to 2.0.15

Snyk has created this PR to upgrade org.slf4j:slf4j-log4j12 from 1.7.25 to 2.0.15.

See this package in maven:
org.slf4j:slf4j-log4j12

See this project in Snyk:
https://app.snyk.io/org/taeb3/project/c86a3b86-7ef6-4639-ae70-73c2e5c97a5f?utm_source=github&utm_medium=referral&page=upgrade-pr

java/client/pom.xml

@@ -14,7 +14,7 @@
     <properties>
         <commons-lang.version>2.6</commons-lang.version>
         <commons-lang3.version>3.8</commons-lang3.version>
-        <slf4j-log4j12.version>1.7.25</slf4j-log4j12.version>
+        <slf4j-log4j12.version>2.0.15</slf4j-log4j12.version>
         <slf4j-api.version>1.7.25</slf4j-api.version>
         <junit.version>4.12</junit.version>
         <guava.version>30.0-android</guava.version>