Bump slf4j.version from 1.7.30 to 1.7.31

Bumps `slf4j.version` from 1.7.30 to 1.7.31.

Updates `slf4j-jdk14` from 1.7.30 to 1.7.31
- [Release notes](https://github.com/qos-ch/slf4j/releases)
- [Commits](https://github.com/qos-ch/slf4j/commits)

Updates `slf4j-jcl` from 1.7.30 to 1.7.31

---
updated-dependencies:
- dependency-name: org.slf4j:slf4j-jdk14
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.slf4j:slf4j-jcl
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index b1744e7..efbdc35 100644
--- a/pom.xml
+++ b/pom.xml
@@ -249,7 +249,7 @@
         <spring.version>5.3.8</spring.version>
         <springws.version>3.1.1</springws.version>
         <exam.version>4.13.4</exam.version>
-        <slf4j.version>1.7.30</slf4j.version>
+        <slf4j.version>1.7.31</slf4j.version>
         <jetty.version>9.4.42.v20210604</jetty.version>
         <log4j.version>2.14.1</log4j.version>
         <groovy.version>3.0.8</groovy.version>